1995 50hp Johnson Fuel Probs?

[natestep]

I am working on a 1995 50hp Johnson. It takes for ever for the boat to plane out. When running the motor on muffs it runs great. Put it in the water and it really loses power. I have had the carbs rebuilt and even replaced the carbs with different ones. The compression is good and equal on both cylinders. The spark is good and blue on both and I have replaced the plugs and wires. I appears that the engine is flooding real bad due to when you stop it in the water it idles down and dies. Then you have to wide open throttle it to get it to start back up then it smokes really bad. The plugs are also really wet when removed after the engine has been running. I have looked for a fuel pump and been unable to find one. It has the pump for oil injection but this has been blocked off and have been mixing oil in the tank. I also check to see if the engine would run better if I choked it a little and pumped the bulb. The engine would start to die out when I choked it and the bulb was really soft and did not change the way the engine ran. Im lost please help.

 

[natestep]

Re: 1995 50hp Johnson Fuel Probs?

Surely someone has had this problem before.

 

[chadpcb]

Re: 1995 50hp Johnson Fuel Probs?

Your motor has a VRO2 fuel pump.
Portside of the engine right behind the air silencer.
Never had that problem you mentioned but I do have a theory.
You may want to check the floats in the carbs. If they stay open they will pour fuel into the engine which would explain a a soft primer bulb.

 

[Rick.]

Re: 1995 50hp Johnson Fuel Probs?

Your motor has a VRO2 fuel pump.
Portside of the engine right behind the air silencer.
Never had that problem you mentioned but I do have a theory.
You may want to check the floats in the carbs. If they stay open they will pour fuel into the engine which would explain a a soft primer bulb.

i think chadpcb has a good theory. With the engine turned off, pump your bulb until firm. You should reach a point where you can't pump it anymore and it will be very rock solid. If it never gets rock solid that is a sure sign your leaking gas through the needle and seat of at least one of your carbs. Your comment about all the smoke when it does fire is normal for an engine that is flooded. At his point I would say your problem is carb. related and you may want to strip them down and give them another cleaning. If you haven't put new kits in them I would suggest you do so now. Best of luck. Rick.

 

[natestep]

Re: 1995 50hp Johnson Fuel Probs?

I had the local marine shop build the carbs. They did put kits in them, when I took the carbs back apart myself I found that they had installed new gaskets, orings, and needle and seat. I held the carbs up and blew into the carbs to insure that the needle was closing off on both carbs and they checked out fine. The other carbs that were bought were supposed to be rebuilt carbs also. It also has a new fuel filter. I was thinking about it last night and Im wondering now if it might be the primer pump that is maybe applying gas to the carbs even when the key is not getting pushed in. Thanks for the suggestions.

 

[Rick.]

Re: 1995 50hp Johnson Fuel Probs?

That's easy enough to check. Have someone listen for the click it makes when the key is pushed in. No click on the second push you could assume it's still open. I doubt that's the problem though. Rick.