Help motor only running on primer!!

[Fishinmission20]

I have a 9.9/15hp force that came with a 9.9 and a 15hp carborator and carb mounting plates. It runs amazing with the 9.9 carb first pull starts good excelleration and speed, but as soon as the 15hp carb is put on it requires the primer to be pushed every few seconds in order to run. This that have been tried: new gasket where it touches motor, new float bowl gasket, cleaned many times with carb cleaner, air compressor, soft wire, 24hr soak in parts cleaner

 

[Nordin]

Check the fuel pump diaphragm.
BTW Why put a larger carb on if it runs good with the smaller?
Maybe the size of the jetz do not match the engine.
Does the 9,9Hp and 15Hp have the same displacement?
A larger carb does not give any amazing benefits.

 

[jerryjerry05]

Year?? Model? They used a few different carbs over the years???
If it needs the choke then the jets might need cleared?
I use a welders orifice/tip cleaner.

 

[Fishinmission20]

Year?? Model? They used a few different carbs over the years???
If it needs the choke then the jets might need cleared?
I use a welders orifice/tip cleaner.

Everything is from 1998 but the engine block is a 1989 15hp block, the 9.9 carb is from the original 1998 and the 15hp carb is from the 1989. It does not care if the choke is pulled or not it needs primer regardless and all of the jets have been cleaned

 

[jerryjerry05]

If the carbs clear and the jets clean then I'd check the fuel pump.
You say primer you mean the squeeze ??

 

[Fishinmission20]

I meant this primer that goes straight into the carb not the primer bulb, it utilizes the same fuel pump for both hp so I just leave it alone, after i attempt it to run there is fuel in bowl and when I take the primer off fuel comes out. It seems as though fuel can’t get to the engine unless I prime it

 

[jerryjerry05]

I'd take the fuel pump apart. One kit to rebuild the carb about 10$ depending on where you get it??
There's one gasket under the FP cover that's NLA s don't mess it up.
The seals in the hose/connector and connector on the motor can crack and suck air.

GASKET/DIAPHRAGM SET 818043A1 for 9 and 15 ​

 

[Fishinmission20]

I'd take the fuel pump apart. One kit to rebuild the carb about 10$ depending on where you get it??
There's one gasket under the FP cover that's NLA s don't mess it up.
The seals in the hose/connector and connector on the motor can crack and suck air.

GASKET/DIAPHRAGM SET 818043A1 for 9 and 15 ​

The only problem is have not switched the fuel pump when switching carborators because they are universal so I know that is not the problem. And a carb rebuild kit is 40-50$ for this motor which makes me reluctant since the parts all look good inside

 

[jerryjerry05]

Your primer might be bad? Once it feeds then it should just stand by as the pump feeds the carb??