Mercury Outboard 175hp help!

[friskylizard]

I have a '89 mercury 175hp that has been to the mechanic 3 times. When i first start it and run it for about 5 minutes under load its fine but as soon as want to go full throttle it only pulls 3100 rpm for about 30 seconds and then drops power and the engine dies. But, every once and awhile it will go full power and get up on plane like nothing is wrong. The fuel line is new, there is spark on all cylinders and i have a new water/fuel filter inline. Has anyone else had this problem??

[upnorth]

I had a problem with gasline bulb on my boat once where if it was either flat or angled the wrong way the little back flow check ball would not allow enough gas through to run full throttle.

[use2bwalleyefanatic]

I had the same problem as upnorth.

[marine_man]

Everything stated so far is good stuff to check...

Did you stabalize your fuel system before storing it over the winter? It almost sounds like a carb cleaning might be in order...

And if you've had it to the mechanic three times why haven't they figured it out yet?

marine_man

[friskylizard]

Thanks for the input.

UpNorth - what did you end up doing?I do have a new bulb/hose. The gas tank was drained for the winter and it does have seafoam in it now. I should say that i took it back to the mechanic and also made him do a "check-run" with me after he pulled the plugs (checked for spark) and pulled the jets. Of course when he was in the boat it got up on plane.

[marine_man]

Quote:

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The gas tank was drained for the winter

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Was the motor run until it died, meaning that the carb bowls were empty? Seafoam helps, but if your carbs are gunked up bad it won't quite do the job.

marine_man

[fchambers]

I had the same problem 2 years ago when the local boat dealer put on a new gas hose. They put it on backwards. I didn't realize it at the time but there is an arrow on the hose that points in the direction of the gas flow. It was backwards. I switched it around and the motor worked great.

[upnorth]

I just cut the hose so that the bulb, when put on with gas flowing the proper direction was slightly slanted down from the motor.