My Tractor Forum banner

Help with Briggs OHV 14.5hp engine

4K views 77 replies 11 participants last post by  zarich 
#1 ·
I am at a loss here. My riding mower uses a Briggs 14.5 OHV 287707 model engine. I have replaced the starter, the armature, the spark plug. I have set the gap on the armature to .010. I have reset both valves to .003 intake and .006 exhaust. The mower will fire once right away and then stop. The plug will be coated in gas. Sometimes it will backfire instead of fire. But that is all I can get.. fire once stop. Fire once... stop. I have tried a different plug, but the result is the same.
I cannot for the life of me figure out what the issue is.
 
#2 ·
I hate to tell you, But you wasted money on the starter:tango_face_crying: The most likely source of your problem is your carburetor. The float is most likely sticking and allowing access gas to get in the engine.

Have you had the engine for a while or did you just get it? The reason is that if it has been sitting a while the float can get stuck. Although when they sit the carbs usually get plugged from old gas anyway.

I would rebuild your carb, or at the very least take it apart and look at, it if it's gummed up or rusty then it will likely be your problem. Sometime's they look good but still have issues but normally that's just a little dirt that got in it.

It's not too hard to fix carbs, You can look up videos on youtube. If you have a basic knowledge of mechanics and some tools you should have no trouble at all.

Hope this helps!
 
#3 ·
Sorry I should be clear. The starter was bad last year. So was the armature. I got this from a guy who left it sitting and replaced those parts to get it running.. which it did all last year. This year.. it is not running at all. I have taken the carb apart before so that shouldn't be an issue. I will give it a go.
 
#4 ·
Check your flywheel key if it'll fire 1 and stalls you possibly have a sheared key if it's backfiring it's a good indicator when mine sheared a key it would fire 1 and the starter would spin the engine over like there was no compression and smoke would come out the muffler if yours does this check the key if it's broke put a new 1 in and impact the flywheel nut on to stop it from flaking on you as I could never get it tight enough to stop it from breaking keys till I got mad and impacted the nut on yours maybe a bolt you can still impact it on tho
 
#5 ·
Oh whoops, Forgot to mention the flywheel key, That is a possibility. I had the exact same engine you had and I couldn't get it to start, turns out twas the flywheel key.
 
#6 ·
My craftsman sat 6 yrs before I got it the acr was bad on the 16.5hp ohv so it kept breaking keys bc the compression relief wasn't happening for easy start but the starter I had was an opposed twin starter that I converted to a single engine starter problem was it was so strong in torque if you didn't have that nut tight enough the flywheel would slide snapping the key
 
#10 ·
I hear ya man:sterb003::sterb003: I've never had anything blow up on me either. lol
 
#11 ·
Yeah the opposed didn't blowup completely but if you read the post I have on b&s opposed twin I'm still having to put 75 into it with brand new valves as the1 that got stuck is completely History got stretched and lost its tempering and now hits inside the head on the left side it ran fine after I got it unstuck for last summer but I used during the winter and that's when it started knocking from the valve hitting inside the head
 
#12 ·
So I am in the process of pulling the nut off to view the key. I did clean out the first part of the carb (bowl, needle, and blew it with a can of air, plus carb cleaner) and that didn't seem to change anything. Backfiring.. should call it forward firing since the muffler is forward has gotten worse.. sounds like a shotgun now. I gave up last night after looking all over for my large socket wrench. I am about two steps away from tossing this. I got it free and just to get it running replaced about $100 worth of parts.. last year had to replace all the belts, then near the end of the year it started dying going up hill.. like crawling up hill.
I don't know small mechanics at all.. this is only my second engine.. the first one I tried to rebuild was an old honda harmony and I blew it up because I didn't set the governor correctly (It was also free and I only put $80 into it).

so... I am learning as I go.
 
#13 ·
It's baby steps bud take it easy and pace yourself as you go don't get frustrated you'll get the engine going a Honda engine is very complicated compared to a Briggs as Briggs haven't really changed since the 40s they just got bigger and materials used have changed but there all timed the same basically with a dot to dot timing system let us know when you check the key if it's broke just put a new one in and tighten as much as you can if it continues to break do what I did take an impact wrench to it
 
#14 ·
Yeah, It's very easy to get frustrated at engines. I normally talk(yell) to them as if they know what i'm saying:tango_face_devil:
 
#15 ·
I swear and growl and throw things sometimes I'll stomp on the junkpile and my neighbors say I sound like lunatic I tell em I never claimed to be sane lol karate chopped my engine cover and crushed it next day I was straightening it back out asking why did I do that lol
 
#18 ·
As said before a very simple engine so look for a simple fix.

You say the plug is gas wet so that infers no spark so here are 2 simple checks:

1) Take the plug out and check for a good spark while spinning the engine.
As you say the timing is all lined up properly so if a good spark then it's a fuel problem.

2) Assuming a good spark try to start it using an ether type aerosol. If it runs on the ether then it's a fuelling problem.
 
#19 ·
Hmm back fires and sputters still seems an issue of timing the key might not be broke but that just means that something else could be wrong the acr could be damaged spray a little gas down the carb covering the bottom this should be enough to give her a whirl if it runs then it's something simple as a dead filter keep in mind the original stock filter is screened not paper if the engine has an external fuel pump run by impulse from the engine the pump could be bad or the filter could be restricting if it's not a screen filter
 
#20 ·
Problem found! No clue how to fix. On the bottom of the armature is a black wire which I believe is the kill switch. If I disconnect this the motor fires right up. However.. I learned that it is a bad idea to pull the plug wire to stop the engine.. when will the tingling stop? All seriousness. I followed the wire back to it's first connect where it plugs into another set of wires along with a grey wire. if I unplug this connection with the key in the run position it makes a click noise. If plug it back it in makes a click noise. With the key in the off position it does nothing.
Lost on what to do next.
 
#26 ·
that sounds like the wire you are unplugging might not be the coil ground but the feed to the carb antibackfire solenoid ,if it has one. There is nothing in the coil grounding circuit that should click. You can run a new wire from the coil grounding tab to a simple toggle switch and to a ground point. You can then control spark with that toggle switch. but after killing engine do not leave the key in 'run' as the carb solenoid could drain the battery over a long sit.
 
#21 ·
I was afraid of that :/ you'll have to remove the protective jacket and find the break in the harness nightmare it could be grounding out on a positive live wire or melted to another positive wire you'll have to unbolt the engine and remove it but label your coil ground out wire so you can trace it back to the break the buzzing could be the fuse no biggy or a relay if the machine has them it could even be a safety switch causing your issues as over time they corrode pto and seat switch can be bypassed to confirm by closing the circuit with a piece of wire a brake switch has to be open so you can just unplug it and not run wire in it
 
#22 · (Edited)
I have already tested all the switches and they all work. The mower is one that will not turn over at all if any of the switches is bad (Key will just act dead as a door nail). Also the fuse is fine. So are you saying I am grounding out somewhere? I shouldn't have to unbolt the engine. Only two wires go under the engine.. the black kill switch wire and a grey one. Everything else is fairly easily accessible except that it is all wrapped in a black bundle.
What exactly am I looking for?
 
#23 · (Edited)
Yeah if you already tested all your switches it could be in the jacket somewhere label the ground wire for the coil on the harness then remove the engine this will let you get to the wiring harness so you can unplug it and remove it so you can check it over cut the ties or tape off the black tube jacket so it can be removed then inspect the wires you should see it right away it'll either be bare or melted into another separate them and rap them individually to prevent a ground out then put the jacket back on the harness and plug it all back in make sure to label each switch plug in so you can have it in easy sounds tedious in writing it's really not so bad
 
#24 ·
Alright. So I have pulled all the electrical tape off the wiring and can't find a break. However after messing with all that it will start now, but start means.. super slow, pop, pop, pop, pop, until finally it either dies or goes kapow! with a backfire.. at 1030 at night. My neighbors love me.
so.. no idea. I tried readjusting the valve clearance to the higher spec, but no dice.
 
#25 ·
Ok so it has to be a break in your harness if you unwrapped it and it wanted to start how much harness were you able to check when you did the valves did you notice if the intake valve bumped after closing this is a compression relief bump that helps the engine to rotate easy for easy start if you didn't see it the acr is bad and you need a heavy duty starter to start that engine as the regular starter isn't strong enough to start the engine does the engine spin by hand easily or hard
 
#27 ·
So.. more updates. First off you are correct the clicking is the solenoid for my fuel. It hasn't worked in forever. I ended up chopping the top of it off since It was originally not letting fuel go. Still doesn't pull the needle, but now it clicks. That being said this morning I tried several tests. If I pull the kill wire from the armature the mower will fire up in less than 1 turn and run like never before.. I don't know if all my tune ups have helped, but it is pushing pretty hard and fast and sounds fantastic. I turn off the fuel and it dies. I tried this several times and it runs great (though I think it is running a tad fast.. which worries me). So definitely a wiring problem. I have found no obviously broken or burnt wires. So I assume I am looking for a line that has no continuity when the key is on. Speaking of when the key, that is the only switch I haven't really figured out how to test.. it has tons of wires going into it.
So.. from what I can figure.. the yellow wires are the circuits that must be open to start.. such as the seat. The orange wires are the contacts that must close. For both the blade and the foot brake it has both. With the blade off and the brake pressed the orange close and the yellow open on both switches. I have pulled the seat and reverse switch as those are both must be open to start.
The mower starts fine as long as the black is disconnected. So all those switches are doing their job normally.

The only thing that stops the motor is the key in the off position normally (or no gas). So I am assuming the key in off does something to the black wire to cause the armature to cease firing. The wire that connects to the armature is black which feeds into another connection that is yellow. That connection also has an orange wire, but it goes to a grey wire that goes to the fuel solenoid. From their they appear to head to a bundle that then heads to the key. The armature is grounded to the motor normally. if I touch the end of the black wire before it goes into the yellow wire and the motor I get continuity. So the black wire is good. However I am unsure what the wire is suppose to do. I am assuming at this point I need to trace that wire, but with the key in the on position.. what should be happening.. with the key in the off position what should be happening?
 
#28 ·
Well good job figuring out what wire was bad now you just gotta find out why your armature ground is staying grounded with the key in run id run a new 1 outside the harness to it to see if you can use the switch if not the switch is bad and can be replaced your almost all set
 
#29 ·
The black wire is a ground out for the armature in off position it grounds out and stays off till you put the key in run position again id say you should recheck or eliminate the bad harness wire as there is a damaged wire you can't see just bypass it and run a new wire for the armature back and do what 38racing said run a toggle switch for your armature ground the toggle switch to the body and run the other to the armature you'll have to turn it on to use the machine before attempting start but that's better than hunting down a new harness
 
#31 ·
That's what I was thinking I suggested a visual inspection of the full harness out of the machine to look for breaks or possible melt together a but he didn't see any so I'm baffled on this there's usually a sign of a ground out could the switch be malfunctioning internally and a plate is bad in it for contacts
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top