[Y Block]

Hey guys, I have a BBC Toro that I just repowered with a Suzuki 2-stroke. It starts easy and runs great with no load. The blade engages fine. But once the blade is turning the engine starts surging and letting out puffs of smoke. I assume there's a fuel system problem? Or could it be the dreaded throttle rod wear? :dunno:

Also, I've got to pull the muffler and check for carbon buildup. It runs WAY quieter than my other 2-stroke Suzuki, almost too quiet. And a couple sparks came out of the muffler when I put it under load the first time. Maybe some residual fuel? :dunno:

 

[GTP]

Hey guys, I have a BBC Toro that I just repowered with a Suzuki 2-stroke. It starts easy and runs great with no load. The blade engages fine. But once the blade is turning the engine starts surging and letting out puffs of smoke. I assume there's a fuel system problem? Or could it be the dreaded throttle rod wear? :dunno:

Also, I've got to pull the muffler and check for carbon buildup. It runs WAY quieter than my other 2-stroke Suzuki, almost too quiet. And a couple sparks came out of the muffler when I put it under load the first time. Maybe some residual fuel? :dunno:

Sounds like a clogged muffler if you put it in the light and look on the exhaust port side of the muffler you should be able to see the mid muffler baffle that will have either a few larger holes or many tiny holes depending upon the year. Take a flat head screw driver and scrape clean all those holes.

Then check your main jet - sounds like it is getting done debris caught either that or fuel filter is clogged. Would create the rich surge. Mine did this and I dunk the carb into my ultrasonic carb cleaner for 15 minutes and it was fine. You might have a muffler and carb thing going on.

 

[podor]

You can spray a little carb cleaner around the carb to see if it is a vacuum leak. I agree with GTP. It sounds like fuel delivery or exhaust. I think the jet is accessible without pulling the carb. My 26682 did the same because carb cleaner made the rubber seat swell and it wouldn't flow enough fuel. I would clean the main jet and check fuel flow to the carb and check the muffler.

Somewhat related, I'm toying with sticking a 2 cycle jet in a 4 cycle carb. They will bolt right up, and the 4 cycle carb has a better throttle set up.

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[Y Block]

Okay guys, I'll see if I can pull the muffler tomorrow and see what's up. BTW, it starts fine either cold or hot and will keep on running.

 

[Y Block]

Well, someone clearly did some work on this thing recently because it's extremely clean. The muffler's clean as a whistle and the exhaust port is clear. The carb is also very clean on the outside but there's a lot of play in the throttle shaft and there's some smudge collecting there. So I assume the carb needs to be replaced. Good thing I got a spare. Does anyone have any tips for removing the carb without destroying the linkages?

 

[GTP]

Well, someone clearly did some work on this thing recently because it's extremely clean. The muffler's clean as a whistle and the exhaust port is clear. The carb is also very clean on the outside but there's a lot of play in the throttle shaft and there's some smudge collecting there. So I assume the carb needs to be replaced. Good thing I got a spare. Does anyone have any tips for removing the carb without destroying the linkages?

Double nut the end of the stud ... Use the inner nut to break the stud fee and its easy as pie.

 

[Y Block]

Sounds tricky. There's no risk of the stud breaking off?

 

[podor]

It should be fine. The key is to keep the force in a twisting motion instead of just pushing on the wrench to prevent bending the stud. Get the two nuts as tight as possible. If you rotate the inner nut when you remove it instead of the outer, it will keep them tight together. I usually slide a box end wrench over the stud before I put the nuts on to use it on the inner nut. If it is super tight, use a wrench on each nut at the same time. I got a carb off with just taking the right stud out, which cut down on the stress a little. I think you can also take the governor arm off, but you will have to re adjust.

You may want to pull that other carb apart first and clean it. Just in case. Be careful with carb cleaner on the seat. I destroyed a perfectly good one because the rubber swelled and didn't flow enough fuel.:banghead:

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[GTP]

You guys may want to go to harbor freight and get an ultrasonic jewelry cleaner. You can use this with plain water, it uses electrostatic pulses and vibrations that clean the small passages and rubber squeaky clean with out chemicals that can warp rubber. They are $35 range and are absolutely worth the investment. All my carbs come out shiny silver and clean as new.

 

[Y Block]

Do you still have to take out all the plastic parts? Like the throttle/choke bushings?

 

[Y Block]

Okay, got the carb replaced. Runs better now. I had to use the pilot jet from the first carb. It now seems to have a little trouble with warm starting but it was much worse with the other pilot jet. One of the carb gaskets is broken so I'll order a new set. I also need to adjust the governor spring because it's running a bit slow.

 

[GTP]

Do you still have to take out all the plastic parts? Like the throttle/choke bushings?

No just disassemble as much as possible....and drop it in.

 

[GTP]

Okay, got the carb replaced. Runs better now. I had to use the pilot jet from the first carb. It now seems to have a little trouble with warm starting but it was much worse with the other pilot jet. One of the carb gaskets is broken so I'll order a new set. I also need to adjust the governor spring because it's running a bit slow.

Don't stretch or shorten the springs, I usually just drill a very small hole it the gov arm and adjust it that way...

 

[podor]

Okay, got the carb replaced. Runs better now. I had to use the pilot jet from the first carb. It now seems to have a little trouble with warm starting but it was much worse with the other pilot jet. One of the carb gaskets is broken so I'll order a new set. I also need to adjust the governor spring because it's running a bit slow.

Great! Glad its running better. Love to see some pics.

I bought the $30 ultrasonic cleaner from harbor freight last week. Ive cleaned 3 carbs so far. Its pretty amazing. I use a biodegradable degreaser from Zep. Its gental on the rubber and adds a little extra cleaning power. I like it because my garage is in the basement. Everytime I look at carb or brake clean my wife can smell it. Not to mention my costly mess up with carb clean. Here are a few pictures of the end result.



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[atomix]

first, Y Block, make sure you have the governor adjusted per the manual. You may have a spring problem as well, but first...
https://www.google.com/url?sa=t&rct...=jozm7ElA5fKrwb9sYWurUg&bvm=bv.49784469,d.dmg
That engine seems very sensitive to air getting in, and the carb good at letting it in if the throttle shaft is worn.

I would like to add more wholehearted praise for the HF cleaner, especially for small bits. Podor, how many cycles is that? I usually say "good enough" after 3 hot 8-minute cycles, with Simple Green Extreme...and I'm not sure I get that clean!

I put whole cylinders and a briggs crankcase in there too Heat is a big catalyst!

 

[Y Block]

I'll try to get some pics soon guys. I've been checking out a new green mower this afternoon. :fing32:

 

[Y Block]

Well, I guess it's not working as well as I thought. I went to start it and the carb had emptied the tank and flooded it. isgus: So I guess I have a bad needle and/or seat. I hope I can get a good carb out of the two bad ones. Do you think I can replace the throttle plate on the worn one? Or is the carb body worn?

 

[podor]

Dont do anything yet. Its possible that the second carb was just gummed up and the float stuck. I have had a few that were like that. I would clean both. Worst case scenario would be to put a shut off in the fuel line. I would highly recommend getting the ultrasonic cleaner also. It is really fantastic. I think both carbs would be ok after a few rounds. It is worth the money.

 

[podor]

first, Y Block, make sure you have the governor adjusted per the manual. You may have a spring problem as well, but first...
https://www.google.com/url?sa=t&rct...=jozm7ElA5fKrwb9sYWurUg&bvm=bv.49784469,d.dmg
That engine seems very sensitive to air getting in, and the carb good at letting it in if the throttle shaft is worn.

I would like to add more wholehearted praise for the HF cleaner, especially for small bits. Podor, how many cycles is that? I usually say "good enough" after 3 hot 8-minute cycles, with Simple Green Extreme...and I'm not sure I get that clean!

I put whole cylinders and a briggs crankcase in there too Heat is a big catalyst!

I ran them through for 9 minutes total, rinsed them in water and dried with compressed air. I have the small one, and it stops at 3 minutes. I didn't warm the solution either. I'll try that next time.

 

[Y Block]

Dont do anything yet. Its possible that the second carb was just gummed up and the float stuck. I have had a few that were like that. I would clean both. Worst case scenario would be to put a shut off in the fuel line. I would highly recommend getting the ultrasonic cleaner also. It is really fantastic. I think both carbs would be ok after a few rounds. It is worth the money.

I hope you're right but the throttle seems to have lots of play on the first one. I'll pull the jets and make sure they're clear. Both look fairly clean inside.