I have a B&G 25HP Twin engine. I rebuilt the engine last year due to broken piston/connecting rod. Ever since the rebuild I can't seem to set the Idle/Running RPMs properly. For this engine I believe they are idle@1750, running @3600. The springs are in the right place and the governor arm has been adjusted properly. What happens is the following. I set the running (full throttle) RPMs to 3600 by bending the spring arm, then move the throttle level down to idle and set it using the idle screw on the carburetor. When I go back to full throttle the running RPMs vary between 3200 and 3400 and the engine sputters and backfires. I can see the governor arm moving rapidly back and forth while it's doing this and I'm assuming that this action is causing the engine to sputter like that. I then reset the running RPM back to 3600, and engine runs smoothly. When I go back to idle mode the cycle repeats. I now have the throttle hard wired to full throttle and I'm running it at 3600RPM all the time. Which I guess is ok for getting the job done, but I'd rather have it setup properly. I used the original springs and governor when I rebuilt the engine. Any ideas?
Running/Idle RPMs
- Thread starter amentac
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Hammermechanicman
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If the engine is surging or "bouncing on the govenor" the mixture is wrong. Set the high idle at 3600 then slowly move the throttle control back to the low idle position. Does the engine at some point start surging? Does carb have an idle mixture screw? If you hold the carb butterfly against the idle stop does engine run smoothly? Are you sure you do not have an air leak in the intake between carb and heads?
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Need the engine's model and type numbers.
A lot the v-twins uses a governor idle setup and the tuning has to done a particular way.
Also did you do a static governor adjustment before even attempting to tune the carburetor?
A lot the v-twins uses a governor idle setup and the tuning has to done a particular way.
Also did you do a static governor adjustment before even attempting to tune the carburetor?
This engine does not have an mixture screw, only idle screw. I did set the governor lever with engine off. I would appreciate if you can send me the correct procedure. Unfortunately I can't get to the tractor right now to give the model number.
I still can't get it to run properly. As I mentioned before my engine model is 445777-0154-E1 and I've since found out running RPM should be 3300 (not 3600). I can set idle RPM as per instructions above, but setting running RPM to 3300 causes engine to sputter. It runs ok at 3600. See video here (note that idle RPM is set a bit high on video)