I'm not a mechanic, or an experienced boater, but I AM handy enough to take something apart and put it back the way I found it. That said, here's all the information I know to provide.. will gladly answer any questions for more details.
A note here, the engine is an older model. It's on a 1971 hull, but outboard is more likely an after market from sometime in the 80's. I've already had the engine half way taken apart (major outer structure only, no moving parts) to diagnose the issue.
The engine, when hooked up to a gas line, leaks. I've tracked down the leak.. it looks like it's coming out of the cylinders. When the choke is closed, I can visually see the choke flap shutting.. and the leak stops. When the choke is open, it leaks. The suggestion given to me was that something was stuck open? No idea here. So, the question.
I'm handy enough to put things back together after I take them apart.. If I strip down the engine and make sure it's all put back together, will it solve the issue here or is it likely to need parts/more work than a simple rebuild? I already know that it also needs a new starter, but after looking at it I already know I can handle that much. (find it.. a whole different matter)
Re: Older model 85hp Mercury Outboard fuel leak issue
There is a sticker or tag with a Mod# and ser# always include that so we know what were working on.
If your getting fuel in the cylinders it possible the fuel pump is defective.Rebuild it.
That way we can figure out the year and get the right parts and repair manual.
Done a compression/spark check??
The miss at low speed could be the air screw needs adjusting.The miss at higher speed could be water in the fuel.
Cleaninmg the carb.Take a couple of pics before disasembly.Then removed the carb and take it apart. The front/side has a screw that controls the air/fuel mixture.Remember the setting for that screw.Turn it in(gently) till it just stops(gently).Remember the setting.
Use any off shelf cleaner.Then use tip/orafice cleaners on the jets.
Reassemble and put the air screw back where it was.
Final tuning is done in the water.Engine warm and in gear.
Turn the air screw in till it makes the motor cough/buck/stutter.Then out 1/2 turn
RPM's 750-800 in gear. Good luck,Jerry
IF YOUR OUTBOARD DOESN"T START WITHING A FEW SECONDS THEN SOMETHING"S WRONG!!!!
boats . net is NOT the place to buy parts.They managed to screw up my last 4 orders.
NO communication,NO follow through. Incompetent staff.Nuff said!
Buy American made Cars and Trucks!!!Towing insurance for a boat,a GREAT thing.
If you fix your problem,do the rest of the posters a favor and send in one more post telling who,what, how it was fixed.J