engine stalls whilke trying to accelerate forward

[neoluddite]

I have a 1984 seaswirl, 18 foot with C/C and I/O, rebuilt ford 3.8 L engine with 800 stringer. After she's warmed up, while in neutral, she will rev fine if you push the throttle forward, or back, and she shifts into forward or reverse, no problem. She also will accelerate fine while in reverse. The probelm is, she hesitates, then stalls when I try to accelerate forward. The carb is squeaky clean, all new fuel lines, new gas (with stablelizer). Also, while shifted in forward, I can accelerate by lifting the accelerator rod on the right side of the carb, no stalling or hesitation. It only stalls if I use the shifter to accelerate while in forward. Any ideas?

 

[Failproof]

Re: engine stalls whilke trying to accelerate forward

Start with a linkage check. Does the accel pump actuate when moving throttle? Is this a sudden thing? Or something that has been escalating? If you pump the throttle lever will it still stall? How about very slow aplication of throttle?

 

[cr2k]

Re: engine stalls whilke trying to accelerate forward

Check the shift interupter. May have slipped.

 

[Howard Sterndrive]

Re: engine stalls whilke trying to accelerate forward

ditto on watching the linkage and specifically the switches that activate your ESA (electronic shift Assist) while someone else drives. The ESA system must be checked in the lake, as propeller resistance in the water is required to make it operate properly- on the trailer or tied to the dock fine.

The ESA stumbles the ignition to assist in gear disengagement. It may also assist in engagement. but, it shouldn't stay engaged when you try to accellerate unless cables are out of whack or a switch is sticking. You can temporarily unplug the ESA module to eliminate it during testing (but don't leave it unplugged -it will make it hard to shift to N).

p.s. your engine is a Chevy 3.8L (229), not a Ford

 

[neoluddite]

Re: engine stalls whilke trying to accelerate forward

It came on suddenly while i was cruising at about 30mph, the engine started hesitating then stalled. (i thought i had ran out of gas, as the gas gauge kept spiking back and forth, but nope, plenty of fresh gas). It re-started no problem, and I was able to accerate while in forward and got back to the dock, but since then, it won't accerate in forward without stalling. Tried a slow accelerate, but it still hesitated and stalled. If I pump the throttle level while in forward it doesn't stall, accelerates fine. How do I check the accel pump, where is it?

 

[Howard Sterndrive]

Re: engine stalls whilke trying to accelerate forward

She also will accelerate fine while in reverse.

the accelerator pump wouldn't work in Reverse and not in Fwd..... which is why we're focusing on cables and the ESA... you could still unplug the ESA module and try it.

but if the problem is a general power issue - might be bad gas, a plugged fuel filter or anti-siphon valve at the tank, or failing points in the distributor. or even a loose spark plug wire or bad plug. Also could be sticking, gummed up advance weights and springs in the distributor or a plugging flame arester atop the carb.
You also can easily check for fuel in the yellow/clear hose from the fuel pump to the carb. fuel in that hose indicates a ruptured fuel pump diaphragm and will cause severe flooding under way.

there's a good checklist in the "adults only" sticky in this forum for checking low power at WOT

never hurts to pull plugs and look for moisture that would indicate a failing riser gasket, then you can inspect the plugs and do a compression test while the plugs are out

the choke heat tube from the intake to the carb like to rot off and create a vacuum leak on those 3.8's also - something else to check