150 mariner problems

[edeuka]

will not idle smooth and runs poorly under 1500 rpms i installed water seperator,plugs fuel line ball and rebuilt fuel pump no change need help

 

[AndyL]

Re: 150 mariner problems

Can you give some idea of the age of the engine and hours run. Has the problem just occurred or is it something that is getting progressively worse.

 

[ufm82]

Re: 150 mariner problems

The carbs need to come off and be cleaned. You probably have dirt or garbage in the fuel bowls and it has clogged the idle passages. Many outboards will run great at full blast but won't idle properly because the idle circuit is clogged. You'll need to pull the carbs and have them gone through. <br /><br /> A short term check to try to fix the problem would be to rev the engine in neutral and clap your hand over the intake- the high vacuum can sometimes suck a piece of dirt through a passageway or jet and let the engine idle better. If this does work at all, it is a good indication that you need to pull the carbs- they are dirty. If it doesn't do anything, you know the carb definitely needs to come off. The motor should run better for a few seconds simply because it will draw in a little better fuel charge for a second with the intake closed off. <br /><br /> Being as it's a Mariner and they haven't been made for a while, I would say that the carbs are highly suspect here. You've done the easy things and rightly so- now it's time to go a little deeper. After you get the carbs done, you may want to think about a decarbon job too.<br /><br />UFM82

 

[screeech]

Re: 150 mariner problems

Thanks for the info.<br />I have a 94 merc black max 200 that has the same problem as above. Won't idle smoothly until about 1500 rpm runs fine above that. My mechanic has tried a bunch of stuff and cost me a bunch of dough trying to fix it. I think he tried everything but the carbs. Time for new mechanic.

 

[edeuka]

Re: 150 mariner problems

1990 150 mariner don't know how many hour on it but compresstion is 90 -92- all cly how big of job is this rebuilding carbs

 

[AndyL]

Re: 150 mariner problems

I had a 135 that had similar problems and spent heaps trying to fix it but never really made much difference. Turned out in the end to be a failing bottom crank seal. The new owner is delighted with once it was changed as I ended up part exing for new motor as it got too expensive and too much wasted time. Obviously you will have to chase the more easy and obvious causes before contemplating pulling the power head off. Can be a real nightmare if the long front studs are siezed into the exhaust plate.<br />I wish you good luck and hope to follow this thread to successful conclusion.<br />Andy

 

[screeech]

Re: 150 mariner problems

eudeuka, hope you dont mind me chiming in. <br />Andy, thanks for the info. That is one suggestion that I have not come across. Are there any other syptoms to look for in leaky seal. I do get a bit of oil in the bottom of my couling.

 

[AndyL]

Re: 150 mariner problems

I doubt if you would notice oil in the bottom cowling. My symptoms were erratic and "wobbly" idle. Occasionally very difficult to start but plenty of power at the top end. I tried everything with much help from this board but never significantly made it better. The crunch came when my wife refused to come out in the boat as starting was awful sometimes.<br />I part ex the motor for a new 150 Mariner and the workshop I sold it too took the powerhead off. The bottom seal was all but failed but no damage to any of the bearing surfaces. They replaced the seal and sold the motor and it is as good as new. It was 11 years old when I sold it which is why I suggested that it may be a similar problem in this case. It may just be something to look at if nothing simpler solves the problem/<br /><br />Andy

 

[edeuka]

Re: 150 mariner problems

pulled carbs off what a dissapointment no dirt in bowls clean as awishle sent dad down to get new gaskets he returned with different bowl gaskets i called back down dealer said thats what mercery says is in there wrong answer put back togather with old bowl gaskets no change to idle next weekend going to mix gas in 5 gal can dissable oil injectoin to see if that makes any change any other ideas i'm open for suggestions thanks

 

[fierro]

Re: 150 mariner problems

i had a simular problem with my mariner 150.icleaned out my carbs with seafoam and pulled all six plugs ,filled each cylinder with seafoam let it sit for 3 hours improved performance and also compression come up from 95 psi to 105 on every cylinder.

 

[edeuka]

Re: 150 mariner problems

where do you buy this sea foam