Hi all,
I've been trying to get out 1988 Mercruiser 3.0 up and running for a few week. Redid the spark plugs, distributor cap, cables, etc. Electronics seem to be fine. We replaced fuel filters and followed the whole line up to the carb, and it's pumping fuel into the carb. It ran for a few days but then died on the water while idling and wouldn't start again. So I finally took the plunge and rebuilt the carb yesterday with a kit and a bunch of YouTube videos.
When I hooked it back up, I can get it to start if I pump the throttle and/or spray a bunch of starter fluid, but it won't stay on unless I keep pumping the throttle. Even if I open it up and push the throttle forward, it won't keep running. Some notes:
1. When I rebuilt it, I couldn't get the jets out (the top was worn from a previous person trying to unscrew them), but we let it soak for a few days in cleaner and sprayed it out; both jets allow spray to come out fine.
2. I couldn't find a check ball under the accelerator pump and spring. Some forums online said that Mercury had taken those out. The kit came with a couple balls, but I couldn't see a way to install it in the cylinder and have it sit still. The spring isn't as wide as the space, there isn't really any "seat" that would hold it in place, and no clamps/rings that i could find would fit in anywhere there. So I've left it out.
3. The second check ball, underneath the venturi assembly with the T-shaped pin and small spring, I checked and cleaned. This part isn't on the instruction sheet, but a replacement T and spring were included in the kit. I used the old ball.
4. The float bowl fills up ok, I took the assembly back apart to check. Would the adjustment on the float have an effect like this? The bowl was filled to about 1/4" from the rim of the throttle body.
5. Spraying carb cleaner into the jets has it come out the other end into the throttle body, as far as I can tell.
6. Chokes adjusted to be almost fully closed when cold. After trying and starting if for awhile, it was starting to open up more as expected. I think it's set right.
7. There is a screw on the throttle portion of the carb that pushes against a cam that's linked to the choke. I set this, according to one set of instructions, but seating it against the cam with the engine off, then tightening it two full turns. I think it sets the idle RPM. Doesn't seem to matter much since no amount of throttle makes it start or stay on![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Any help or suggestions would be appreciated. This is my first boat and first time working on engines/carbs.
I've been trying to get out 1988 Mercruiser 3.0 up and running for a few week. Redid the spark plugs, distributor cap, cables, etc. Electronics seem to be fine. We replaced fuel filters and followed the whole line up to the carb, and it's pumping fuel into the carb. It ran for a few days but then died on the water while idling and wouldn't start again. So I finally took the plunge and rebuilt the carb yesterday with a kit and a bunch of YouTube videos.
When I hooked it back up, I can get it to start if I pump the throttle and/or spray a bunch of starter fluid, but it won't stay on unless I keep pumping the throttle. Even if I open it up and push the throttle forward, it won't keep running. Some notes:
1. When I rebuilt it, I couldn't get the jets out (the top was worn from a previous person trying to unscrew them), but we let it soak for a few days in cleaner and sprayed it out; both jets allow spray to come out fine.
2. I couldn't find a check ball under the accelerator pump and spring. Some forums online said that Mercury had taken those out. The kit came with a couple balls, but I couldn't see a way to install it in the cylinder and have it sit still. The spring isn't as wide as the space, there isn't really any "seat" that would hold it in place, and no clamps/rings that i could find would fit in anywhere there. So I've left it out.
3. The second check ball, underneath the venturi assembly with the T-shaped pin and small spring, I checked and cleaned. This part isn't on the instruction sheet, but a replacement T and spring were included in the kit. I used the old ball.
4. The float bowl fills up ok, I took the assembly back apart to check. Would the adjustment on the float have an effect like this? The bowl was filled to about 1/4" from the rim of the throttle body.
5. Spraying carb cleaner into the jets has it come out the other end into the throttle body, as far as I can tell.
6. Chokes adjusted to be almost fully closed when cold. After trying and starting if for awhile, it was starting to open up more as expected. I think it's set right.
7. There is a screw on the throttle portion of the carb that pushes against a cam that's linked to the choke. I set this, according to one set of instructions, but seating it against the cam with the engine off, then tightening it two full turns. I think it sets the idle RPM. Doesn't seem to matter much since no amount of throttle makes it start or stay on
Any help or suggestions would be appreciated. This is my first boat and first time working on engines/carbs.
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