1987 Mercury Two Stroke 90HP motor issues.

[pontoon_guy_2017]

I have a 1987 Mercury Two Stroke 90HP motor on my 1993 24ft Sundancer pontoon. I bought the boat last summer and the side cowling on the motor was missing. Anyways whenever I take my boat out at first I have to spray starter fluid in the top carburetor while cranking to get motor to start. I recently changed the spark plugs and the fuel filter in hopes that might resolve the issue. However it didn't and last time I took boat out I had to spray starter fluid in carb while cranking. I'm considering taking boat to mechanic but wanted to see if there is something else to check on my own to try and save some money. Any feedback is greatly appreciated.

 

[racerone]

Serial # is ?-------3 cylinder or 6 cylinder ?---Are you pushing key in while cranking it over ?

 

[Little Richard]

Maybe butter flies on carb not closing all the way when your trying to start it and it's not pulling fuel. Once you get it started can you kill it and fire it back up. Not familiar with your motor.

 

[JDusza]

Ouch!!! I would highly recommend you do not use starting fluid. It burns exceptionally hot and may ruin a piston.
You definitely have a fuel delivery issue. And, for these you have to start at the beginning...be sure you have a fresh mix of fuel. Don't dilute the old stuff with new stuff. Be sure you are completely rid of the old stuff.
Then your carburetors need a tear down and rebuild with special attention paid to the low speed jets being clean.
If you're mechanically inclined, you can do a rebuild. For insurance, take digital pictures so you don't get lost at reassembly.
J