Engine Bogs/Stalls at quick WOT/ dieseling when shut off at times

[ZXREDWING91]

Hello, I have a 4.3l LX engine with a weber Carb 9600s 1374. The problem I am having is the engine will bog if I go to WOT quickly. If i do it instantly it will stall completely. I am able to go a 1/4 throttle and than ease into full throttle with no problem at all. There is no hesitation in the motor other than going into WOT quickly. Also at times the engine will diesel when shutting down the motor. Any help would very much appreciated. Has a new water separator and fuel pressure checks out to be good.

 

[Bt Doctur]

dieseling is the worst, to hot, too lean, too fast

 

[ZXREDWING91]

Can you please be more specific?
The water temp stays in the normal range.
Can I change to less lean?
You say to fast? Am i driving the boat to fast??

 

[Bt Doctur]

engine temp 160 or less
for lean idle open up the idle mix jets more
too fast of an idle speed, less than 800 in gear, in the water
incorrect engine timing, too far advanced

 

[ZXREDWING91]

Thank you! Any idea for the bogging issue? would you recommend a rebuild on the carb? Thank you for your time.

 

[Bt Doctur]

 

[Scott Danforth]

specifically the accelerator pump shown in the lower left hand corner of the kit that GA posted.

 

[GA_Boater]

specifically the accelerator pump shown in the lower left hand corner of the kit that GA posted.

I did? I see BT's pic. LOL

Bogging as you describe is usually caused by a non-working or marginal accelerator pump. The shot of gas richens the mixture to get over the hump when the throttle is bumped quickly going from low to higher RPMs

Do the complete kit that I didn't post the picture of. :smile:

BT's advice about the lean idle, idle speed too high and timing is right on. Rebuilding and adjusting the carb should cure everything except timing.

And oh, :welcome: aboard.

 

[ZXREDWING91]

Thank you very much everyone for the information. Ordering parts now.