9.8 hp Tohatsu smokes on startup

BobGlover

Seaman
Joined
Jul 27, 2003
Messages
65
My 9.8 Tohatsu starts ok, but really smokes on the first startup. On subsequent starts, it smokes much less. Any ideas what’s wrong?
 

airshot

Rear Admiral
Joined
Jul 22, 2008
Messages
4,380
If a two stroke it is normal as left over fuel residue inside the cylinders evaporates leaving just the two stroke oil. First start burns up all that extra oil resudue. If a four stroke engine then some compression testing should be done to check the motors health
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,509
Yes. if the old 9.8B, it will smoke at initial fireup. If an MFS9.8A or B it might be overfilled with oil, or over choked.
 

MattFL

Master Chief Petty Officer
Joined
Oct 20, 2010
Messages
845
Cold 2-strokes will smoke. Also some 2-stroke oil is smokier than others.
 

BobGlover

Seaman
Joined
Jul 27, 2003
Messages
65
Yes. if the old 9.8B, it will smoke at initial fireup. If an MFS9.8A or B it might be overfilled with oil, or over choked.
I finally took it out of the lake! It’s a 10 yr. old NSF9.8A3. I ran a compression test, and it’s got 125 psi on both cylinders. However, the plugs look oily. I changed them several years ago, but the motor hasn’t been used much. The oil level is ok, on the lower half of the stick. Was changed last spring. Why would the plugs foul so quickly?
 
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