Merc 90 starting problems.

screedee

Senior Member
So, I put my boat up for awhile, had two kids. Finally, got back down to lake to see if it would start(kind of thought it might not) been sitting for over a year)
My question: Where do I start to get it running again?

1. It turns over just fine, just wont fire up.

2. Always been run ethanol free.

Is the gas probably bad?
 

660griz

Senior Member
Yep. Bad gas most probably.
I had the same issue. Got fresh gas and poured Seafoam in the carb and the tank, and let it sit for a minute. Fired up and ran good from then on.

I had some starter fluid with lubricate. Not really good for a 2 stroke but, I needed to know if it would fire. It did, knew it was the gas/carb.
 

1gr8bldr

Senior Member
If it's been sitting, and it is a 2T, then the gas has evaporated leaving a bowl full of oil. The float continues to allow more fuel, that evaporates, leaving more and more oil. Especially on a gravity fed higher tank like a dirtbike. Yours will likely just be what was in the elevated lines. The jets although nonethonal fuel, may be blocked. Not sure if you have a bowl drain???? A bowl overflow drain will not get it. If you have a bowl drain, then new gas and draining the bowl with a little fresh fuel as a flush may get it clear. The carb works on atmospheric pressure just as water seeks to level itself, so does barometric pressure pushing fuel into the ventri. If the oil in the bowl is deeper than the jet openings then it will not pick up fuel
 

speedcop

Senior Member
if you have fire to your plugs( you do dont you?) then you have a fuel/carb problem
 

kranich

Member
Is it a 4 stroke or 2. If 2 then like the other gentleman said the carbs are probably full of oil and no gas. Drain carbs and get good fuel going to them. If 4 stroke then your high pressure fuel pump inside vapor canister most likely needs to be cleaned. Just did my 50 this past weekend due to it setting up.
 
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