View Full Version : Problem with b66 Evinrude 95 HP

Tom Zeltwanger
07-05-2001, 09:08 PM
" Just got an old boat with an Evinrude SportTwin 9.5 HP motor, vintage 1965. I have cleaned up the motor and it runs great but ONLY WITH THE ENGINE COVER OFF! It runs with the cover on but it struggles and is obviously lacking power. When I added some new gas to the tank (that contained who-knows-what) it ran for about an hour but then it was hard to even start it. I already rebuilt the carb, thinking this was a needle valve, float, or air leak problem -no real improvement.

Could this be a problem with the fuel supply equipment and not the motor? Fuel pump symptom? "

Tom Jefferson
07-06-2001, 08:53 AM
" Check the rubber exhaust hose between the inner and outer exhaust housings for leaks or cracks. It will leak and allow exhaust gas to be inhaled by the engine, causing a similar problem. "

07-06-2001, 10:53 AM
"Tom.... You don't say if you're running that engine in a barrel or while you're under way in your boat. If you're running that engine in a barrel, the hood must be off. With the hood on, the engine will draw in its own exhaust to the carburetor instead of good air.


Tom Zeltwanger
07-06-2001, 03:08 PM
Thanks for the comments -

This happens either in the barrel or underway. Thanks for the tip - I won't bother running it in the barrel with the hood on again!

Also I will check the exhaust hose to make sure it is not suffocating itself. I just got a new gas line and a new can with clean gas just to be sure.


Tom Zeltwanger
07-06-2001, 09:16 PM
Found the main problem. The insulation inside the cover was loose on one side. When it ran for awhile I think the insulation near the carb was collapsing and cutting off the air supply. I cut away some of the loose insulation and it runs much better.

Is the insulation necessary for anything? Can I get replacement material?

Thanks for your help.

07-06-2001, 09:35 PM
"Tom.... That insulation material is actually soundproofing. Not really needed, a matter of choice.


Robert G. Lang
08-16-2003, 04:46 PM
" I need a gas tank for a 30 HP 1956 Evinrude, 25022-0507. Where cabn I find one? "

Robert G. Lang
08-16-2003, 04:47 PM
"I need a gas tank for a 30 HP 1956 Evinrude, 25022-0507. Where cabn I find one?

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