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I have an 84 40 horse 3 cyl that I've owned for the past 11 years. It's a pretty clean motor and has been pretty reliable in the time I've owned it minus a few hiccups. The last 2 years it hasn't been running.. at first it would start up and wouldn't stay running. It would idle for a few seconds and then die, but would stay alive longer if choked while idling. Whatever I did though it wouldn't stay alive longer than 3-4 seconds and I couldn't get it in gear. My thoughts were air leak or dirty carbs.
What I've tried:
- cleaned the carbs twice. I've done this numerous times since owning the boat so it's not new to me. I boil them in vinegar now and blow everything out with compressed air. The first time I did it after the no starting they were the dirtiest I had seen them in all the times I've cleaned them. Full of goo. Put them back together tried to start it up and still nothing. A few months later I get interest again, take apart the carbs and they're once again very dirty with orange residue. So they got boiled and cleaned again.
- changed the oil pump (new oem) and oil lines(clear)
- changed all the internal fuel lines (clear)
- new spark plugs
- new fuel tank
- new primer bulb and fuel line
Now it won't start up at all unless I spray premix through it. I can crank and crank it and it sounds like it's not getting fuel. No hint of trying to fire. If I spray premix through the carbs it will fire right up immediately and die after 1-2 seconds. Primer bulb will get hard and it's filling the carb bowls. I've verified by undoing the 10mm brass screw on the sides of the bowls. I've checked the plugs and they look barely wet or on the dry side. After cranking the motor several tries the primer bulb stays hard. Everything seems to point to the cylinders not getting fuel. What's got me even more stumped is it seems like it's all three cylinders. When I spray premix through one cylinder at a time, I can hear that cylinder trying to fire. So whatever this is is an all 3 cylinder condition.
Any ideas what would keep all three cylinders from getting fuel when the carbs are clean and bowls full? Compression is about 80 psi on all cylinders. I know that's low but it's been that way since I bought it. Sorry for the long read and thanks for the help.
What I've tried:
- cleaned the carbs twice. I've done this numerous times since owning the boat so it's not new to me. I boil them in vinegar now and blow everything out with compressed air. The first time I did it after the no starting they were the dirtiest I had seen them in all the times I've cleaned them. Full of goo. Put them back together tried to start it up and still nothing. A few months later I get interest again, take apart the carbs and they're once again very dirty with orange residue. So they got boiled and cleaned again.
- changed the oil pump (new oem) and oil lines(clear)
- changed all the internal fuel lines (clear)
- new spark plugs
- new fuel tank
- new primer bulb and fuel line
Now it won't start up at all unless I spray premix through it. I can crank and crank it and it sounds like it's not getting fuel. No hint of trying to fire. If I spray premix through the carbs it will fire right up immediately and die after 1-2 seconds. Primer bulb will get hard and it's filling the carb bowls. I've verified by undoing the 10mm brass screw on the sides of the bowls. I've checked the plugs and they look barely wet or on the dry side. After cranking the motor several tries the primer bulb stays hard. Everything seems to point to the cylinders not getting fuel. What's got me even more stumped is it seems like it's all three cylinders. When I spray premix through one cylinder at a time, I can hear that cylinder trying to fire. So whatever this is is an all 3 cylinder condition.
Any ideas what would keep all three cylinders from getting fuel when the carbs are clean and bowls full? Compression is about 80 psi on all cylinders. I know that's low but it's been that way since I bought it. Sorry for the long read and thanks for the help.
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