Bent floats cause this symptom?

[rothfm]

I put this motor together...Machined 1984 block, new pistons/rings/bearings etc...Been running great. Until last trip.

For the issue, just tonight I swapped the VRO/Fuel pump unit with another (I mix), and did a complete carb rebuild properly( Berrymans, wire and air). Will test tomorrow.

THE QUESTION: I found the original floats bent at a decent angle, where the bowls would probably fill with a lesser amount of fuel when the needle shuts off the supply.

THE SYMPTOM: Would bog and try to die only once at planning speeds 3000-3500 after 15secs or so. Backing off the throttle to idle for just a couple seconds would allow another short run. YES, squeezing the bulb, or hitting the primer--WOULD DEFINETLY ALLOW it to run at speed. I could actually keep hitting the primer and continue to run, sort of.

This is not a Tempature issue, as I monitor closely..I know these motors pretty well. I am currently using double oil during my breakin, due to the new pistons and rings. The carbs were original 1984, and personally I hadn't rebuilt them before last night. They looked clean.

CAN THOSE BENT FLOATS DO THIS: A short run, then run out of fuel until they fill up again??

Thanks

 

[Bosunsmate]

Yes thats possible.
If priming the bulb manually works, check also for air leaks and the fuel pump itself, does the bulb prime up fast?

 

[emdsapmgr]

What hp engine are you working on? If the engine is consuming more fuel than the fuel pump can supply, it could also be the sign of a weak fuel pump. You'd get the same symptoms.

 

[Tim Frank]

and did a complete carb rebuild properly

If you'd done it "properly", you'd have set the floats per spec.

Not sure what motor you have, but there is probably a thread in here that has that spec.....it's a good reminder of why an OEM manual is invaluable.

 

[rothfm]

Fixed. And I got to say due to these forums...I was able to immediately isolate to fuel, and narrowed down the issue.

I always use the OEM manual.. Johnson 115. Swapping the vro/fuel pump and the carb rebuild did the trick. Wish I know which it was but needed to get back running asap.

It was either the floats in the orig carbs, or I feel like the pump was breaking down and starving the motor. Nice to have extra parts to play with

Test run tonight went well, all rpm ranges..Still using double oil for a few more hours.

Thanks all.

 

[Tim Frank]

Love the good outcomes! Well done.