Mercury 40 HP problem....HELP!!

[sailfish1]

dont know if this will help, but you could check to see if you have a knob inside the motor that will change the gas /air mixture. if your fouling plugs, it could be running to rich and just needs a little leaning out. the knob inside of mine is bright red

[Slipped Cork]

If oil on the plug that mean's that plug wasnt firing.Do the check test and let me know along with the other's the result's.I never use sea foam but it might be a good thing,I dont know anything about that stuff.If your gas and oil mixture is correct you should have no problem with gumming issue's.A worn or broken ring on the piston can cause this issue also as it will not allow enough pressure to push the gas into the chamber.Do the test with the plug first and let us know.

[SpeckWick]

Got home late tonight and haven't had a chance to check things yet. Had to get the boys to a ball game. If I get a chance before dark I'll check the plugs and the vents and whatnot and get back. Thanks for hanging with me.

[SpeckWick]

OK, just checked for spark. I have spark at both plugs. I started the motor. It started on the first crank. Ran for a minute in idle and died. When I tried to restart it, it wouldn't at first. I put it in neutral and opened it up. It started and sputtered and spit blue smoke, then ran okay, but not at low idle. When I was trying to restart it, I walked back and noticed gas coming from the front of the carb. Flooded, obviously. I have a neighbor who is an auto mechanic and finally caught him home and he seems to think it's the carb diaphram or float allowing it to flood. He says this will cause fouled plugs and all the other symptoms I have. The vent is clear, I have spark. I am inclined to believe he may be right. It all makes sense to me, but again, I'm no expert. Is he wrong? Any other things I should check first? I am hoping to limp through a tournament this Sunday and next Sunday then I have the whole month of July and August to get it rebuilt. Am I taking too big a chance to run it this way?

[Barnacle Bill]

OK, just checked for spark. I have spark at both plugs. I started the motor. It started on the first crank. Ran for a minute in idle and died. When I tried to restart it, it wouldn't at first. I put it in neutral and opened it up. It started and sputtered and spit blue smoke, then ran okay, but not at low idle. When I was trying to restart it, I walked back and noticed gas coming from the front of the carb. Flooded, obviously. I have a neighbor who is an auto mechanic and finally caught him home and he seems to think it's the carb diaphram or float allowing it to flood. He says this will cause fouled plugs and all the other symptoms I have. The vent is clear, I have spark. I am inclined to believe he may be right. It all makes sense to me, but again, I'm no expert. Is he wrong? Any other things I should check first? I am hoping to limp through a tournament this Sunday and next Sunday then I have the whole month of July and August to get it rebuilt. Am I taking too big a chance to run it this way?

Yup, you need to rebuild the carbs using new needle and seats. They are really very simple to rebuild once you get them off. As long as its flooding the cylinder instead of running dry it won't hurt to run it. You might try adding some Seafoam to the gas. You might get lucky (and thats a big might).

[Slipped Cork]

I agree with IBNFSN and your neighbor.As long as the cylinder is getting fuel,oil mixture you will be ok.I would take an extra plug or 2 to limp through those tournament's but you should get the carb rebuilt soon.Be glad it wasnt a power pack lol.

[SpeckWick]

Thanks for the help. My neighbor has offered to help me/show me how to get the carb off and rebuild it so hopefully next time I won't be totally lost when a problem arrises. I'll try the Seafoam stuff, too. I'll add some now, then once we get the carb rebuilt I'll start using it regularly. Question is how long has this problem been going on? I've been thinking I had the weakest 40 HP motor on the water and it may just be a carb issue all along. Thanks again for all the help. This site is the best.

[Slipped Cork]

I bought a new 25hp mercury a few year's ago and it didnt run right.I pulled the carb off and the float was close but not right.With a little tweaking it ran perfect.Not even factory made mean's it's right.Let us know if the rebuild help's.

[grubby]

Glad you got a good neighbor after you see him do it and check the float level to see if it is letting too much fuel in. you will see just how simple the carbs are on an outboard are to work on and you said you have some mechanical ability so the next time you will have the confidence to do it yourself.

GOOD LUCK AND GOOD FISHING.

[BULLFROG-1]

Thanks for the help. My neighbor has offered to help me/show me how to get the carb off and rebuild it so hopefully next time I won't be totally lost when a problem arrises. I'll try the Seafoam stuff, too. I'll add some now, then once we get the carb rebuilt I'll start using it regularly. Question is how long has this problem been going on? I've been thinking I had the weakest 40 HP motor on the water and it may just be a carb issue all along. Thanks again for all the help. This site is the best.

Them 40 merc when tuned and tweaked right are not weak motors at all.