4.3 GL won't run over 2000 rpms under load.

[alldodge]

I'm getting around 7 psi between the pump and carb.

With 7 psi your in great shape, but does it stay that way as you increase speed under load? Need to see what it goes to when you cannot get above 2000 rpm in the water

 

[NWFL Chappy]

Ok, will get it in the water and try Wednesday after tomorrow's Holiday frenzy.

 

[NWFL Chappy]

Put it in the water today to get some readings. Between the tank and fuel pump, it reads zero at idle and barely moves off zero at WOT which still doesn't exceed 2000 rpms. Between the pump and carb, 7-7.5 at idle, 8-8.5 at WOT. Talked to Marine Mechanic and he says my manifolds and risers may need replacing. How do you determine that?

 

[alldodge]

Recon it time to check the basics.
Start with a compression test, should see around 150 psi
Note how the plugs look
Then timing

If VP used exhaust flappers I would check them, but they don't. As for the manifolds I don't see them getting clogged, rusted thru and leak water but not clogged. Could take the boots off the risers to the Y pipe to check for obstructions

 

[NWFL Chappy]

I'm getting 170 psi on all cylinders but #2 which registers zero.

 

[alldodge]

I'm getting 170 psi on all cylinders but #2 which registers zero.

You lost 1/6th of all your hp and its probably a valve issue. Could be burnt, stuck, warped or broke valve seat. Guess it could also be a head gasket but those usually happen between cylinders. Time to pull the head and have a look

 

[RCSConstruction]

I'm getting 170 psi on all cylinders but #2 which registers zero.

Pull the valve cover first. Look for loose valves train components. You may have to spin motor over a little if not obvious. (try to get TDC)
May be just a pulled rocker stud.Pretty common and fairly simple fix

 

[12milogu]

Yes, or even harbor freight, just google "vacuum fuel pump gauge" it will show several. The issue is getting the fittings to fit the pump to carb with a Tee.

You could order one of these which fits between the fuel line and carb. Might have one at AZ
View attachment 237359

What is this special tee called?

 

[Bondo]

What is this special tee called?

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