3.0L Mercruiser Engine Bogging, Hesitating, Surging

[fraserjr]

Hi All,

Everyone here is always a great help so I figured I would pose another question/problem. I recently installed a rebuilt carb. It is a 2bbl rochester to replace the 2bbl mercarb for my 1989 3.0L mercruiser. At the same time I switch from a points system to a Delco Voyager EST marine electronic distributor kit:

http://www.michiganmotorz.com/3.0L+Delco+Voyager+EST+marine+electronic+distributor+kit

Since the install I have had surging, bogging, loss of power and hesitating with anything beyond half throttle. When I am WOT, I am at about 3000 RPMs and only doing about 15 mph. Previously I was at 4200 rpms and about 30-34 mph at WOT.

If I manually push the choke more closed I get a lot more power. Any thoughts as to what this could be? I am thinking the new carb, but am not sure what next steps to take. Any help would be appreciated.

Thanks in advance,

John

 

[cooter2506]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

it sounds fuel related. Go to the adults ony section and check out How to diagnose your boats fuel system.

 

[marlboro180]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

Any reason in particular that you went to EST? Was the ignition acting up before? Or just tired of tune-up parts?

Kinda the same question for the carb- Was it acting up? Or were you having runability problems ?

 

[IVAZ]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

If I manually push the choke more closed I get a lot more power. Any thoughts as to what this could be? I am thinking the new carb, but am not sure what next steps to take. Any help would be appreciated.

Thats an indication that you are not getting enough fuel to engine.

 

[fraserjr]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

Any reason in particular that you went to EST? Was the ignition acting up before? Or just tired of tune-up parts?

Kinda the same question for the carb- Was it acting up? Or were you having runability problems ?

There was major grinding noise in the old points system that sounded like there was a gearing issue in the distributor. It was also really hard to get the engine started and actually would not start one day at all on the water when the engine was warm. It was also stalling at idle even after adjusting idle speed on the carb. This was really the reason for replacing both.

 

[fraserjr]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

Thats an indication that you are not getting enough fuel to engine.

Yes, but I don't think it is the fuel system because that was working fine before the carb and distributor replacement.

 

[searay3]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

The rebuild in the carb didn't take. If you bought it from a rebuild shop, take it back. Must have some kind of warranty. If a buddy did it, have to do it again. This time completely. Bad choice to switch both the carb and the ignition at the same time. Get one running then switch the other if you must. I would put the points back in, set it up proper and get the fuel system resolved. Then if you still feel the need, swap the ignition.

 

[IVAZ]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

I wonder if the jetting is the same in both the carbs you have? Have you checked out any of the fuel filters? They are probably not your issue but it would be nice to fully rule them out.

 

[IVAZ]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

The rebuild in the carb didn't take. If you bought it from a rebuild shop, take it back. Must have some kind of warranty. If a buddy did it, have to do it again. This time completely. Bad choice to switch both the carb and the ignition at the same time. Get one running then switch the other if you must. I would put the points back in, set it up proper and get the fuel system resolved. Then if you still feel the need, swap the ignition.

I totally agree with this. It is always better to do one "upgrade" at a time. At this point it really might be better to try to get it back to original, then do one at a time.

 

[fraserjr]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

I wonder if the jetting is the same in both the carbs you have? Have you checked out any of the fuel filters? They are probably not your issue but it would be nice to fully rule them out.

I have checked the fuel filters and they are clean. There did seem to be an issue with one of the venturi's spraying gas, but its hard to see when out on the water. There is fuel coming out of both though.

 

[marlboro180]

Re: 3.0L Mercruiser Engine Bogging, Hesitating, Surging

Yes, but I don't think it is the fuel system because that was working fine before the carb and distributor replacement.

Then why did the carb get swapped out?