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Chinese clone swap into a SS15

13K views 35 replies 13 participants last post by  seedbag 
#1 ·
Hi all, it has been a while , I thought I would share my experience of swapping a 18 hp Duromax into my SS15 build. I could have posted in my build post but thought this might be more suitable for a separate post. I received the engine on Friday with no shipping damage (sigh of relief) Looked it over real good, seems to to be well built, threw some oil into it and some gas. I then attached the switch panel and tried to figure out the wiring, ignored the manual and wire colors and used common sense, I wanted to use the electric start to fire it up to test that side of it. once I had the wires sorted (more on that in a bit) it fired right up, it was quieter then I thought it would be and did not shake much, overall I was pleased with it.







Now the wiring was confusing at first and then it all fell into place, there is one brown charge wire from stator, a black one from coil (ground) a spaded one from switch to the "S" post on Solenoid and 2 black ones from Ignition switch (one for the coil ground and one for the low oil sensor) I will be by passing the solenoid on this using my original and disconnecting the low oil sensor.



I then removed my briggs off the tractor and got it ready for the swap.



Here it is on and mocked up to figure out position, I removed the gas tank because there is no way I could have the engine back far enough with it on

The 2 marks on the frame is where my briggs shaft positioned and where I need to get the 18hp to line up with, then all I need to do is make sure the belt lines up with the pulley on, this will determine where I mark my holes for drilling. I used a cardboard template of the base on the clone engine. I needed to drill 4 new holes. Center of shaft to base on the clone was 5 inches and the briggs was 6 inches, it did not appear to have any impact on the install, just need to adjust the belt tensioner a little.



This is it after drilling and mounting, eevrything looked good except I screwed up with the key on the shaft, it was tight and I tried tapping it in and now it will not go further in or come out (tomorrow's battle) The engine's off to the left but still had room for bolts.





Here you can see where I bolted on my positive battery lead from my solenoid onto the clone solenoid.



I need to install a drain pipe for oil changes.



Side note, when I removed the Briggs engine this was the carb side of the inline filter, amazing it ran.



And this is my newest purchase, a fairly new blade hardly used with a electric winch on it, blade and winch price up to $350 easy, I got it for $125





It does crank up, runs and shuts off on the tractor ignition switch now, that part was easy. More tomorrow when I continue this saga, need to get that key out, get another fuel filter, get another choke cable and hook up throttle cable.

Thanks for looking.
 
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#3 ·
Will do Larry, just glad this will be a help to someone.

I got the key out and installed a new fuel filter and then took the tractor for a spin on the back lawn. It seem to have more speed then before, I went round going over all the leaves that had dropped off our Elm tree and it was pretty deep in places, engine did not slow down one bit and I was only at half throttle. It has plenty of power and torque to spare, even with a worn out deck which has all the pin holes flogged and noisy bearings and bad deck belt.

Here it is at a running stage





Belt alignment



Fuel line



I did a reading of the volts it was putting out of the charge coils and this was at Idle!!



Just need to figure out where to hook the charge wire up to. It looks like I might have to disconnect the original wiring from the amp meter and have hot from the ignition switch to the plus side and the charge wire to the negative side, at the moment it is reverse I am getting a negative charge showing. Do I need to go through the regulator? If some one can chime in here and give me a idea or two it would be great.

Tomorrow I will tackle the air box and exhaust, I have a week off work and this is how I R n R

Thanks for looking.
 
#6 ·
Just need to figure out where to hook the charge wire up to. It looks like I might have to disconnect the original wiring from the amp meter and have hot from the ignition switch to the plus side and the charge wire to the negative side, at the moment it is reverse I am getting a negative charge showing. Do I need to go through the regulator? If some one can chime in here and give me a idea or two it would be great.

Tomorrow I will tackle the air box and exhaust, I have a week off work and this is how I R n R

Thanks for looking.

That charge wire should have had a DIODE. My clone had it on the control box side. It takes the place of a regulator.

EDIT: Should look something like this.
 
#7 ·
It's amazing how they can add more HP to these motors - that looks identical in size to the 11hp Greyhound thats in my ST/12 I am restoring right now. Its a very capable motor too even at 11HP- If this motor has a charging system, it's never worked... The battery will last 30 or 40 starts and will run the headlights for a long time, but I am glad it has pull start on it.






FYI you may get flack from some on repowering a classic, and I used to be one of those nay-sayers, but since I have repowered most of my machines, and I never have to tinker on the repowers, I say go ahead! I am sucking up all the diesels I can find too- I love the smell of a rich diesel in the cool weather :D
 
#8 ·
One other thing, I extended the wires on my ignition switch so i could move it up to the dash. You will need to enlarge the mounting hole in the dash too to accomodate the ignition switch if you do that - I also drilled out the holes to mount the reset switch on my dash.
 
#9 ·
@codeman ''what else are your plans for it?''

Modify the exhaust and air box and modify that snow blade to fit.

@mightyraze ''Diode in wire''

I know what you mean but could not see an obvious one unless it is further back behind the shroud, if it does then that's why I am getting DC voltage.

@GT_80 ''Flak''

That does not worry me, I have kept every thing that's original so one day it can be put back to that condition if I want to. But the Briggs was twice as heavy as the clone and does not run as good. At the moment it is running off my original ignition system. if I extend the clone wiring I may as well remove the old wiring and regulator box and solenoid and just keep the wiring for the lights
 
#11 ·
@mightyraze ''Diode in wire''

I know what you mean but could not see an obvious one unless it is further back behind the shroud, if it does then that's why I am getting DC voltage.
Mine was in the control/key box.
 
#10 ·
Well I am a little stumped, I removed my regulator box but when I connect the charge wire out of the engine to one side of the amp gauge I get a light blue spark and the gauge needle moves off the zero mark 1/8 '' and stays there, it doesn't matter which side I hook up the wire it still moves the needle positive or negative. This is with the ignition off and engine not running. When I get the little spark I hear a light click in the engine.

I did another check of the out put on the charge wire but this time AC and this is what I get at full throttle. There is no visible diode in the wire unless it is behind the shroud. So I am guessing this is AC volts, do I need a rectifier?



Any help here would be greatly appreciated. The wiring is pretty basic that I can see, ground to ignition switch, hot to ignition going to amp gauge then down to solenoid hot side to battery, solenoid "S" wire going from ignition switch down to brake sensor and back again. Not counting the fuse wire which is for the lights.
 
#13 ·
I'm not sure what your motor has on it for a throttle setup, but my Greyhound and the predators I believe all have a throttle lever with holes in it for a cable, and a clamp location near it - see these pics:
Motor vehicle Engine Auto part Vehicle Automotive engine part


Engine Auto part Yellow Automotive engine part Vehicle



The choke I just manually open and close but you could drill a tiny hole in the lever, and use a cable if you get creative with a clamp point. The good thing is, it has no resistance on the choke lever so it would be an easy setup.
 
#16 ·
Got some more done today and made some good progress, hooked up the diode wire and took a reading and got this in DC volts



And got this on the battery



I am thinking it is only a 3 amp charge and not much good for much, that;s OK I was thinking of a mini alternator set up later anyway.

Next job was the throttle cable, I shortened it about 6'' and made a new "Z" then I oiled it before install, I had to make my own clamp and stole a screw off the muffler (Chinese threads=weird) I loosened the big nut on the throttle plate a smidgen to move more freely



Here is the clearance I got on the air box side with the cover off, I will take out a little of the grill knob that you see and grind off a bit of the plastic of the carb cover but it will still be close to the bolt, I can live with it. For a replacement cover for the air filter I was thinking of a heavy plastic jar withe top cut off and a hole in the bottom to mount on the stud. That will kill two birds with one stone, 1 It will eliminate any possible contact and shorts with head lights and 2 It will enable me to see at a glance if the air filter is dirty by looking through the clear plastic cover. Not factory correct but practicable.





Now the fun part, the exhaust, here it is with original muffler and manifold off.



I knew I would need a new exhaust flange but like a dummy I did not order one when I ordered the engine so in the spirit of the home handyman I made my own. I used pretty heavy plate, I wanted to over come the longer studs and be a little beefy. Not perfect but good enough.

http://i998.photobucket.com/albums/af107/Craig_Morrell/Sears SS15/DSCN0182.jpg





Here it is welded up to the pipe. I went over the welds a bit more after those pics.





And mounted on the engine with a bracket I made for my Briggs engine.









The muffler is just sitting on there with no clamp and the support bracket has no foot yet welded on and bolted to frame. I am still going to see if I can just go to a 90 deg elbow instead of the 90 and 45 street elbow but with both on it makes it easier to align the stack more straighter. I am also tossing up the idea of bringing the stack closer to the hood by 1 1/2'' but do not know if the time spent and welding to do it is worth it.

I will finish it off tomorrow and bolt everything on I have off and start it up, I think it will be the same loudness as my briggs but who knows?, it may surprise me.

Thanks for looking.
 
#17 ·
Looks great! I did a similar flange for my muffler. Your welding is much better than mine :) I had to loosen my throttle plate nut too. It's a nylon nut so that should be fine. I've been 2 yrs just fine now.
 
#18 ·
Been following your progress with interest--someday I may find a clone reasonably priced and put it in one of my Suburbans..

You can still find "waste nut flanges" at a good plumbing supply or hardware store,those save a lot of time and effort when making a custom exhaust--not sure if the China engines share the same flange bolt spacing as the usual Briggs or Tecumseh's,but they are a bolt on deal on those...I have used them to repair engines with stripped pipe threads in the exhaust port and create custom exhausts..
 

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#22 ·
Thanks for the kind comments guys,



I got it all together and running and I was getting 12.47 volts at full throttle so I would say it is only a trickle charge, hardly moves the amp gauge if at all. Charge wire hooked to one side of amp and ignition hot wire on the other which goes to the solenoid and then battery.

I took it for a test run and every thing worked great except for the mower deck belt, in my haste I set it wrong on the deck pulley and it folded over and started to smoke on the mule drive. The tractor steers like it has power steering and turns sharper then my snapper and seems more zippy in gears, I am saying that because this really has been the first real test since restoring it. The stack is not too noisy (quieter then the briggs) throttle works good but had to adjust a little, I was not getting full throttle plus I have to tighten the throttle plate nut more because it would creep off full throttle.

I removed the 45 deg street elbow and just used the 90, it worked out good, still straight and closer to the hood. I also rewired the headlights so they unplug on a pin connection, I have pics but Photobucket is not responding and will not up load pics at the moment
 
#21 ·
Sure is looking good man!!! Sweet welds! ;)
 
#23 ·
OK photobucket pulled their finger out and I was able to up load pics, here they are.

A cleaner shot of the exhaust flange.



One of the support bracket.



The rest is out in the yard on it's maiden voyage.









And a rear shot of her in the garage.



Next job is fix rear tires (also tri-ribs for front later), restore deck and make mount for the snow blade, decals later on......and then a mini alternator for extra lighting.

Thanks for looking.
 
#24 ·
Sure looks nice!! Good job!
 
#25 ·
I am really glad to see this and will be following this thread.

My HydroTrac engine, a Tecumseh OH140 repower from 1990, started sounding funny deep down in the spring of 2015 (you'd think you could get more than 25 years out of an engine ;) ) and, not being an engine rebuilder, got opinions ranging from $1000 rebuild to "oh just throw in a new connecting rod".

I bought a new Husqvarna GT52XLS and set it up to work with all my attachments but it's just not as much fun as the old Sears was and I've been playing with the idea of pulling the tractor cover off and installing one of the Harbor Freight engines.

You've given me encouragement. I just wasn't convinced it would all pack in under the hood and look "somewhat" original.
 
#26 · (Edited)
I did basically the same swap in my ST12 after the Tecumseh gave up the ghost. That's the one you see in my Avatar. Princess Auto had a 13HP Honda clone that looks identical to yours in layout.

I removed the self contained starter panel from the motor and tank/battery mounting plate, lined the engine up with the mark I made where the original side shaft was located and got the drill ready. Lo! All 4 holes lined up in the base so it was a quick bolt in.

Surprisingly, after installing the two pulleys I found the original guard also a direct fit to the side of the case so that part was relatively painless.

The most work came from my own idea. I flipped the battery/tank plate as the stock tank was no longer required and this gave me greater clearance to the hood for a larger battery. I had to trim the forward edge of the plate to clear the motor and then cut down the drive tension pulley mount to set the stock height so everything would work the same. Took a few tries to get it right.

The other mods were to build up a new drive tensioner pulley, do an exhaust mod like yours, (only mine is a short stub rather than the tractor exhaust) and trim the hood side plate for the pancake muffler.

That took care of the major bits, but I had to fab an extension for the nose piece and hood to clear the front of the motor. Even with the exhaust mods it was too tight and would have cooked the rather delicate glass nose.

I did remove their drain plug, retap to NPT and install a drain pipe that exits the side of the frame to keep things clean.

Frankly, the most involved was to fab up bracketry and linkages for the choke and throttle. There was no easy way to run the choke around the front without binding so have to admit I dug into my R/C bin and set up a bellcrank and a helicopter main rotor link to change direction.

From there it was integrating it into the existing wiring harness and this is where one of the biggest shortcomings showed up. Their integral charging system is marginal at best and will not rewind the battery at anything below full throttle. As you have seen this uses a simple diode rather than the stock regulator which indicates how minimal the charging system is in this design. I'm thinking before next season I may pull the flywheel to see if it's possible to upgrade the charging circuit.

Other than that the best statement is although it looks like a Honda and their legacy parts fit, I found some serious Q/C issues, (along with a lot more vibration than any Honda I ever used). The first was their oil level switch would disable the ignition with anything less than the level right to the top of the plug threads. The next is this will NOT start cold or hot without full choke.

Another set of problems showed up on an almost regular basis. Approximately two weeks after installation could not get it started. Traced it to a failed plug that would only fire when outside the head. Another two weeks and the same story. That time it was the plug cap and the Honda bits saved the day.

The next issue became evident not soon after. I smelled gas when I got home late one night and with little wind was able to follow my nose around the back. Found the left front tire wet with the line from the tank to the carb weeping down its length. Our fuel contains methanol and I suspect it ate the rubber away. A bit odd diameter but I was able to find replacement and so far so good.

Lastly, (so far) was the starter would not turn. Took it apart and found one of the magnets had come loose. Back to the R/C table and 30 min epoxy did the job.

One of these days it may be worth it to post some pics of all of this.

I do have to say the basic engine mechanicals have held up well. While landscaping our back yard I put a LOT of miles on it towing a grader plate and it shows no signs of wear, (also, no smoke like the Tecumseh, but admittedly that one had 35 years on it:tango_face_wink:).
 
#28 · (Edited)
Thanks guys, it was all worth it, it runs great.

All 4 holes lined up in the base so it was a quick bolt in.

The most work came from my own idea. I flipped the battery/tank plate as the stock tank was no longer required

That took care of the major bits, but I had to fab an extension for the nose piece and hood to clear the front of the motor.

I did remove their drain plug, retap to NPT and install a drain pipe that exits the side of the frame to keep things clean.

Frankly, the most involved was to fab up bracketry and linkages for the choke and throttle.

I'm thinking before next season I may pull the flywheel to see if it's possible to upgrade the charging circuit.

The first was their oil level switch would disable the ignition with anything less than the level right to the top of the plug threads. The next is this will NOT start cold or hot without full choke.

Another set of problems showed up on an almost regular basis. Approximately two weeks after installation could not get it started. Traced it to a failed plug that would only fire when outside the head. Another two weeks and the same story. That time it was the plug cap and the Honda bits saved the day.

Our fuel contains methanol and I suspect it ate the rubber away. A bit odd diameter but I was able to find replacement and so far so good.

Lastly, (so far) was the starter would not turn. Took it apart and found one of the magnets had come loose. Back to the R/C table and 30 min epoxy did the job.
@Cougar429, I condensed your build to some high lights I would like to comment on.

I had to drill 4 new holes probably because the 15 HP Briggs I have is a big engine but I have heard other people say theirs line up also or they had to drill new holes any where from 1 to 3 new holes.

If I remember rightly your clutch is originally mounted to a bracket bolted to the rear of the engine, mine is welded to the bottom of the battery/fuel tank plate. I could have made a new set up and possibly used the tank that came with engine but chose not to, maybe later down the road I will revisit that notion.

I also had to move the mounting holes for the grill about 1/2'' forward and it still is a bit tight by the air filter but I can live with it.

Thanks on the heads up on the drain plug, I thought I could just find a pipe to screw in there but re-tapping with a more common thread makes sense.

The throttle cable was the easy part how ever the choke cable was more of a stumper. I could have used a longer cable and gone around the front but hooking up to the plastic choke lever did not appeal to me. The short time and ease of using the choke out weighed the effort and time to have a choke cable.

Yes you are right the charging system on these clone engines are pretty poor but other people claim that you can get higher amp out put on some, I was hoping my 18 HP was going to be better then what it is (basically a trickle charge of 2-3 amp) I have also heard that there is provision on the fly wheels for more charging coils but I am not sure if you need to swap out fly wheels or what, I think Honda coils fit. I am leaning towards getting a mini alternator off a Kubaltor or Polaris Ranger side by sides (We have them at work for cheap) and mounting one of them, should be able to run all the lights and winches all I want then.

I disabled the low oil sensor light as most people have done but what I was thinking of doing was hooking it up to a idiot light mounted where the choke usually is, it may come on prematurely sometimes but it will keep me checking my oil on a regular basis....and it is better then nothing. Plus I am a little over full (Way over.....cough) on the dipstick.

My engine starts right up on choke (Cold) but needs choke to start and 1/4 throttle (Hot) and anything less then hot then Choke but I shut the choke off straight away once running. Other people said they need full choke to run even, re-jetting for our fuel and altitude maybe?

Again thanks for the heads up on the Plug and cap, I will keep an eye on them and replace when I need to.

On the last two comments, I have heard of most rubber parts on the engines deteriorating over time and loose magnets in starters. Replace the fuel line straight away for sure and others as needed (Air breather hose and so on)

To some these engines up, are they perfect?... **** NO but....do they perform? YES they do and lets face it, for the price I can turn the other cheek for all the little pit falls that come with them.

But it's people like you and others that are willing to share their experience that helps every one get better results from their re-power efforts. These Q&A's are an invaluable source to them. Thanks for your input.
 
#29 ·
Hello, Poppa58 and all your readers: I have installed 15-hp versions of these engines in both the projects I wrote about in MFT ("Hydrostatically driven oddi-T" and "Repower a 1982 Craftsman 20T - hood won't fit"). I thought I'd share how I solved the throttle and choke cable hookups.

I was able to use the stock throttle cable on the 20T Craftsman; however, because it's a bit too short to go around the front of the engine, I built a little bracket and attached it to the Chonda throttle lever as shown in the first photo. I was able to use the factory cable length, and thus also use the factory-made Z at the cable end. Like a couple of you fellows did, I reduced the tension nut to let the throttle lever pivot more easily.

On the Ford Model T, I created one completely custom cable; the engine end is shown in the second photo ... fairly conventional hookup. The black arrow shows that I had to unhook the small return spring (in addition to loosening the pivot tension nut). As for the choke (third photo), I had to kludge up a pivoting cable clamp because the arc of the choke lever would not allow the cable to smoothly operate through its full travel. The agricultural-looking swivel was intended to be temporary, but it works perfectly, so I will leave it "as is". Note that I simply drilled a small hole through the choke lever and made up a simple "L" on the cable end to hook it up. Also works fine. By the way, the fourth photo shows the very handy tool I bought which makes neat-o Z's on the cable ends.

As for the key panel on these engines, I had to re-mount both; the Craftsman remains on the engine, only mounted lower, so it still works as original. I didn't hook up the dashboard choke, so the stock Chonda key panel location works for me. The T-bird was another matter ... I moved it to to the drivers' side of the (wooden) firewall, and discovered that unless you add a ground wire between the metal case of the key panel and the engine block, the engine won't shut off when you turn the key.

Now, about the starting characteristics: Both engines briefly need full choke for a cold start, even in summer weather. Both will run fine with no choke needed after that, unless you have the engine sit unused for too many minutes (depends on the ambient temperature)

Finally, the charging systems on both will nicely keep up with the starter and LED lighting that I use on the Model T. A side note about LED efficiency: I installed four way flashing lights, using an electronic flasher. Although all four lights lit up when manually connecting, the flasher would flash only once or twice and then go dead. I discovered that the four lights collectively used so little current that the flasher didn't recognize the electrical load. I had to install a fifth lamp of conventional incandescent type, to add enough load to induce the flasher to "go to work". The Craftsman has no hood and no other lights, so the Chonda alternator doesn't have much of a chore there.

I hope my comments will be of help to the many people who are considering the installation of these engines. I'd certainly buy another for my next project.
 

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#30 ·
Thats a great thread! I want to hear how it sounds with a stack on it :) I bet it sounds nice and mellow- these motors are generally very quiet as is, and I bet the stack is really nice. The ST/12 I am redoing with the Greyhound 11hp motor in it the muffler is really close to the headlights I put in, and the headlights are plastic housings, so I am going to put an aluminum heat shield on it to reduce the heat a little more before it melts the headlight.

Good job on everything else, I was considering making a choke cable for that tractor as well, but I don't have any really long choke cables so it would mean buying another one for that purpose, and I am not sure I want to, but probably should cause I am selling it to a friend, but I figure he needs to turn he gas on and off, and the choke is right there. YET, I think I just talked myself into it... well, won't take more than a few minutes to rig up the choke cable too.
 
#31 ·
Thats a great thread! I want to hear how it sounds with a stack on it :) I bet it sounds nice and mellow- these motors are generally very quiet as is, and I bet the stack is really nice.
Ok here is a video of it running and revving, I hope the vid is OK I think there was dust on the lens.

 
#32 ·
Aww thanks for the shoutout in the video! Sounds really nice! I did a similar air filter cover on my ST12 I am selling.

use a 16x6.50-8 tube to get the tri ribs on the rims- they will fit. I did it on my GT18
 
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