3.0l hesitating while at crusing speed and bogs when giving throttle

[jimbo1229]

So I installed a new rebuilt carb on my 3.0l beachcraft. The boat will idle fine and run at low rpms but when I give it throttle or I am just cruising it hestitates and drops RPMs. Prior to replacing the carb it ran great other than it would never start do to a bad float. I was at lake mendo 3 weeks ago and it ran bad and then died and would not start, so I continued to try and start it. Im wondering if the plugs got so fouled from me trying to start it for a hour that its causing this problem or using 87 octane gas and letting it sit in real hot weather for 3 weeks has caused it to lose octane? my idle sits at 750 rpms and I do have a water/ fuel separator and new cap,rotor and wires. Any input would help?!

 

[alldodge]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

Gas won't go bad in 3 weeks of hot weather, it will just evaporate some. If you have spark and air the only thing left is fuel. Sounds like you may need to try the rebuild again, but before that check fuel filters, fuel flow and fuel pump pressure.

 

[jimbo1229]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

Fuel filter and new fuel/water separator replaced last month. Im gonna check the plugs tonite they might be bad, I was also thinkn it might be the anti syphon valve. although there is plenty of fuel squirting into the carb so im assuming the pressure is good.

 

[alldodge]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

If you have a fuel restriction like the anti syphon valve or a weak fuel pump, both can cause issue with acceleration and performance. When you back down the throttle there is time for the carb to fill back up with fuel because less is needed. Your fuel pump needs to supply enough fuel under maximum demand otherwise when full load is obtained you start running out o fuel. The pump should put out at least 4PSI average is between 4-6. If there is a restriction the pump may not be able to create enough sucktion to over come it or if the pump is weak. A cheap vacuum/fuel pressure gauge can tell you a lot.

 

[jimbo1229]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

Dodge how would I go about checking the pressure? would I hook it up before or after the pump?

 

[alldodge]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

Put a tee between the fuel pump and carb then connect the gage.

KD Tools Fuel Pump Vacuum and Pressure Tester - Tools - Mechanics & Auto Tools - Diagnostic Tools & Testers

You can find these about anywhere, walmart, autozone, etc.

 

[jimbo1229]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

so dodge i sprayed some carb cleaner around the base of the carb and the rpms dropped, so i have a vaccuum leak. Should i put gasket sealer on the gasket since its brand new and the screws are tight

 

[alldodge]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

You could try sealer but take a close look at the base of the carb and the intake. A new gasket usually fixes a vacuum leak at the base of a carb unless there is another reason its leaking. It could also be leaking from the intake or between the pieces of the carb. Did you disassemble or rebuild the carb?

 

[jimbo1229]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

no bought the carb from a company that gurantees to run and no leaks. im wondering since I didn't buy a merc carb gasket it that's the problem, the company I bought from sent me a gasket.

 

[alldodge]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

Don't think its the gasket unless something happend to it or some of the old gasket was left behind and was not removed. Someone guarantees it to run, well it runs but how good is something else. Not throwing stones I just can not see what your seeing. As before it could also be an intake gasket or vacuum hose leak.

 

[jimbo1229]

Re: 3.0l hesitating while at crusing speed and bogs when giving throttle

So were gonna do the timing this weekend. took it out yesterday and it would fall on its face on take off and not hold a steady engine RPM. im gonna replace the plugs as well and then move to fuel if this doesn't fix it.