1987 Indmar 351w bogs/hesitates upon accelerration

[jbsupreme]

87 indmar 351w with holley 4160 bogs under loaded acceleration. This usually occurs when the boat is warm and trying to pull a skier out. When I am in the cockpit I can ease the throttle and get a skier out, but less experienced drivers have issues.

I have rebuilt the carb and replaced throttle cable, plugs, cap, rotor, checked and adjusted timing, fuel filter, adjusted accelerator pump, fuel nozzle, choke, new adjustable secondary etc... Engine is strong

I have read in a few similar posts that I should check for weak fuel line which I will get into. Still looking at carb, but I think its working well.

Any other ideas?

[TLR67]

Check your filter under your fuel pump...

[thatsmrmastercraft]

How does it behave running WOT? I suspect OK, in which case I would look at the accelerator pump function. The passages for the accelerator pump are quite small and if not completely clean, they will cause a stumble.

[jbsupreme]

replaced fuel filter this season. took the boat out for a few laps today and ran fine. I what would cause an intermittent condition?

[JimN]

87 indmar 351w with holley 4160 bogs under loaded acceleration. This usually occurs when the boat is warm and trying to pull a skier out. When I am in the cockpit I can ease the throttle and get a skier out, but less experienced drivers have issues.

I have rebuilt the carb and replaced throttle cable, plugs, cap, rotor, checked and adjusted timing, fuel filter, adjusted accelerator pump, fuel nozzle, choke, new adjustable secondary etc... Engine is strong

I have read in a few similar posts that I should check for weak fuel line which I will get into. Still looking at carb, but I think its working well.

Any other ideas?

Do you have a vacuum gauge? Monitor that when it's loaded and accelerating- if you're opening the throttle far enough, it'll be too rich when the engine is at normal operating temperature. Might need re-jetting.

[jbsupreme]

"wonder what"

[jbsupreme]

re-jetted when carb rebuilt this season.

[JimN]

"wonder what"

Huh????

[thatsmrmastercraft]

Did you have this problem before you rebuilt your carb?
Why did you re-jet?
What were previous jets?
What did you change to?
Did you use a Holley marine rebuild kit?
How did you clean your carb during the rebuild process?

[Spork]

...........

[jbsupreme]

cleaned carb with gumout. re jetted because i had it open and replaced with stock. replaced floats: adjusted parallel to fuel bowl, Ski-dim kit, substituted stock power valve with quick fuel 2.5.

ill have to pick up a cam kit. I did notice that the fuel line coming from the top of tank makes a hard 90 degree angle into the bilge. I am going to work on making a smoother bend in the line. The fuel line could definitely be pinched off slightly.

Been running well today. havent pulled a skier though...

[thatsmrmastercraft]

This doesn't sound like a fuel supply issue, otherwise there would be problems with overall hard runs and pulling a skier.

Hesitation under load isn't always a carb related issue. I would check the voltage at the positive side of the coil both with the key on/engine off, and with the engine running. Points or electronic ignition?

[waterlogged882]

..........

[jbsupreme]

points, havent rebuilt distrib

but installed new coil, plugs, cap, rotor a few weeks ago

have the quick fuel adjustable secondary, hull is clean.