Gas problem 1992 90hp

I have a pontoon with a 1982 Evinrude 90 hp motor. It has a 6 gallon metal tank under the back seat and a 12 gallon metal square shaped tank sitting on the back.

The 6 gallon is easy to remove, just pick it up, but the 12 gallon is there to stay without some major rebuilding to get it back on.

The motor will run fine, then start slowing down, missing, even die. You can change tanks and it will run fine again...for a while. I have replaced the gas hose and hose fittings, but no help.

My best guess is that both tanks have some trash in them that, with the motor pulling, causes the strainer to stop up after a while. Without the motor pulling with sloshing around, it clears back up.

What I need to know is what is the best way to clean the tanks. The 6 gallon of course has the lip inside so that simply rinsing and turning it upside down will not let the trash out. And, as mentioned, the 12 is more or less there to stay.

Any and all help greatly appreciated.

Re: Gas problem

The symptoms could be those of tanks that are not venting

Try taking the caps off. If that cures the problem then it is venting or lack of.

However if it is debris in the tanks syphoning may be the way to remove it.

Or something like this http://www.pelaproducts.com/

Re: Gas problem

Yes, the 12 has a venting problem and I have learned to loosen the cap. However, it seems to have trash in addition. What do you mean by syphoning? Just sucking the gas out and hoping the trash comes along?

Re: Gas problem

Just sucking the gas out and hoping the trash comes along?

Click to expand...

Yes that's the idea. The Pela or similar would make it easier.

If you can't tip it out sucking it out may be the way to do it.

Re: Gas problem

I assume you've checked for clogged s air vent?