RPM Randomly Drops While Using

[riodecolumbia]

I’m still relatively new to the boating scene, but I’m figuring more and more things out as I go. I have a 1991 Regal Valanti 190 boat with a Mercruiser 4.3L inboard motor in it.

So the motor will work completely fine for like 20 min or so, but after that it begins to experience a problem. The motor will all the sudden drop about 600 rpm or so and then climb back up to where it was at. Sometimes it won’t make it back up to the original rpm it was at, and keep going slowly down until the motor will die. If you wait a bit the motor will usually get started again, but won’t be long before it dies again the same way.

It has a rebuilt carb, and I thought originally the float was getting stuck maybe but the carb is getting plenty of fuel it looks like. I checked the amount of fuel in the tank, and it has plenty of fuel as well. I checked the in line fuel filter as well and it appears fuel is going through it fine as well. So I don’t really know what the problem could be. Any help would be much appreciated!

 

[alldodge]

Initial thought is you need more carb work.
A rebuilt carb may or may not be adjusted correctly. During shipment it can be bounced around enough to change things

Is the choke fully open when warmed up?
When the motor dies, is there any fuel dripping down the throat?
Has fuel pump pressure been check (3-7 psi)?

 

[riodecolumbia]

Initial thought is you need more carb work.
A rebuilt carb may or may not be adjusted correctly. During shipment it can be bounced around enough to change things

Is the choke fully open when warmed up?
When the motor dies, is there any fuel dripping down the throat?
Has fuel pump pressure been check (3-7 psi)?

I have not checked if the choke is fully open, but I will check that next time.

Originally there was fuel dripping down the throat when the motor died, but I adjusted the carb to make it stop doing that.

I have not checked the fuel pump pressure yet, but that was one of the next things I was gonna do.