Motor boggs down after it's on plane.

[duhn]

1988 mercury 150 hp black max.
I took the boat out tonight, and while making a run the motor just bogged down and stalled. Started it back up and tried again. Had to feather the throttle to get back up on plane again. It did it again. Sometimes it will go for a minute sometimes it goes for 5 minutes. No consistancy. Any suggestions?

 

[tashasdaddy]

Re: Motor boggs down after it's on plane.

vent open on fuel tank? did you check spark immediately after it failed. air leak in fuel line. do you have a kill lanyard?

 

[j_martin]

Re: Motor boggs down after it's on plane.

If it's fuel related you could burn it down if you keep trying to run it without fixing it.

First check, fuel pump, fuel filter, water in tank and/or vent plugged. Aftermarket fuel hose and primer bulb. (yep, they won't deliver enough fuel)

hope it helps
John

 

[duhn]

Re: Motor boggs down after it's on plane.

How would I check the fuel pump?? the carbs appear to be getting fuel because I am able to get the boat on plane.

I have a new Mercury primer bulb with an inline fuel filter that is see thru. Sometimes it's full with an air bubble inside, some times it's not full. Pumping it while it is bogging down did not solve the problem.

Another thing I noticed. when the motor is tilted up for traveling on the trailer, fuel comes out of the carbs. It's not supposed to do that, is it?

 

[tashasdaddy]

Re: Motor boggs down after it's on plane.

when you tilt the motor the carbs are out of level, thus the floats are out of the designated postion, what gas that is in the carbs will drain, it fuel line is still connected, and the sun heats the tank, causing pressure, it can still force fuel out the carbs. when tilting, for storage, disconnect fuel line. did you use the correct size fuel line.

you also could be dropping a cylinder or 2, due to coils heating up and failing.

 

[tashasdaddy]

Re: Motor boggs down after it's on plane.

if all else fails this may help. http://forums.iboats.com/showthread.php?t=168855

 

[duhn]

Re: Motor boggs down after it's on plane.

Thanks for your help.

You had mentioned the coil heating up. What would cause the coils to heat up? I have 4 other coils from another older motor that I thought was a problem.I left them in because they were working. I will change them out to the original ones. Would coils heating up have a constant or random effect on the motor?

I am putting the boat in the water this morning for a test run. If the coils are not the problem, I'm gonna try my spare stator that I have.

Any thoughts about my primer bulb having air in it sometimes?

Devin

 

[lowkee]

Re: Motor boggs down after it's on plane.

Was the carb recently gone through? It sounds eerily like a misajusted float. I'd also check for a vacuum issue in the fuel delivery, clogged air inlet in the fuel tank, maybe?

I'd put a few dollars on one of the above 2 things being the cause.

 

[duhn]

Re: Motor boggs down after it's on plane.

Thanks all, I got it fixed. Turns out it was one of the coils. I had picked up some used ones this past summer. I put the original one back on. Runs like a champ!!!!!

As far as the fuel leaking out of the carbs, I just disconnected the line while it was running to run it out of gas. It's probabily better to store it with the carbs empty anyways.

 

[j_martin]

Re: Motor boggs down after it's on plane.

Thanks all, I got it fixed. Turns out it was one of the coils. I had picked up some used ones this past summer. I put the original one back on. Runs like a champ!!!!!

As far as the fuel leaking out of the carbs, I just disconnected the line while it was running to run it out of gas. It's probabily better to store it with the carbs empty anyways.

You got that one right. If the carbs are empty, the float hangs, opening the needle valve. First flush of gas rinses it off and all is good.