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Autolube Mercury only running with choke on

L

loic

New member
Hello,
I've got a mercury that was running fine, but has been left for about a year. It was winterised but has been fired up a couple of times over the course of the year.

Just firing it up tongiht and it's not playing ball. It starts fine with the choke on, but when it runs produces a huge amount of smoke. Then, when you depress the choke, it'll run for a little bit then slowly die. If you increase the thottle it kills it quicker. The second you push the key in and give it some choke it fires back up again, but all the time making loads of smoke.

I'm guessing dirty carbs or something? What's my best course of action to fix this?

Many thanks!
 
You push the key in and hold it in for choke / enricher .--------------Push key in as needed untill motor warms up and runs with no choke / enricher applied .-------------------If you push key in when motor is running / warmed up a bit ,you will flood it !!-------------It does sound like carburetors need cleaning ( floats stuck )--------------Some automatic oilers have been known to leak and put too much oil into the carburetors.-----Dealer can check adjustment on the automatic oiler.
 
OK, so I took the carbs off and they look fine. No gunk in them, only a tiny amount of sediment at the bottom of the pots. I've got to pick up some carb cleaner tomorrow to clear out the jets, but I've got a feeling my problem isn't due to dirty carbs.

If it's not - could it be a head gasket? Can't tell exactly as it happens quickly, but a buddy suspected the engine would start initially OK, then start to bog down when the water started coming out of the little water exit . Could that explain the 'smoke' coming out of it, and that it only runs on the choke on? What can I do to test the head gasket - perhaps a compression test?

It's very strange as the engine's just been sat around, winterised. It was run maybe 5 times last year and that's it. Weird that the gasket would pack up after so little use - the engine ran perfectly before then.

Thanks in advance!
 
Trust me there is no cylinder head on that motor----------thus no head gasket problems.------------Having to keep the choke " on " indicates carburetor / fuel problems.
 
Last edited:
Chaps, I took off the carbs, emptied them out (there was a little sediment in the pots), blasted all the jets out out with carb cleaner, soaked them for 24 hours in petrol (gas), gave them another blast of carb cleaner and slapped them back on.

Engine's running better than it ever has done!

Thanks for your help.
 
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