I'd like add my two cents on a engine not runnin' right. Engine normaly, High
Performance outboard, Highly modified Thunder Tiger , all of a sudden, Bwaaahh
15 mph,,after a normal launch. Checked everything,,Next heat,,same thing,,What
The,,(Won Both Those Heats at 15 mph). Last heat,,engine hard to start, Real
Hard to start,,,Finally it started,,and seemed to wind up a little Too good as the pit
man headed for the water, and me toward the drivers stand. Only to look at my pit man shaking his head "no" and showing me the rear of the boat. OK, back to
the hot pits,,Franticaly,,only to find that the plug had spit out,,Installed new one
quickly and restarted,,same fast walk to the,,and Hey!! "It Spit The Plug Out Again"
That was the last heat of the day and then a two and a half hour drive home. I
Checked the engine out,,What I thought , Totally,,and even took it to the next club
race,, two weeks later,,Ran OK in practice in the morning,,and Bwaaah,,15 mph.
To make this all shorter, I finally found the problem! I had used a different pipe and header combo Three Races earlier,,Almost a month! and didn't change the
Header Spring!! It was too long for the the new combo and it would Blow the
header partly off and sometimes it would get stuck partially open,,it didn't make that much of a noise difference, but I do remember it " winging a "little Too Good"
With semi straight exhaust these motors will wing up to a point where a "Turbo"
grind on a crank will go out of balance and spit the plug out in about 5 seconds.
One simple thing on these motors can drive you Nuts!