Officially Hate my Sport Jet 120 Motor

Frsmith2

Cadet
Joined
Jun 24, 2012
Messages
25
I have spent more time trying to get my "free" boat right than I have actually enjoying it the few times its been right...

Last night, I "fixed" my rich at warm idle issue but another issue was created that didn't exist the last outing.

Background:

Compression in 120 range on 4 cylinders
Reeds look new
New almost everything electrical including stator, starter, rev limiter, etc.
Dissasembled and cleaned carbs that worked flawlessly
New fuel lines
Rebuilt fuel pump
All jet components including ride plate all look fine
Plugs new last season

When right, boat will plane within a few seconds and get quickly to 41 miles per hour indicated. I noticed it ran rich at warm idle and narrowed it down to the enrichner.

In the process, I decided to check carb idle mixture.

I repaired the enrichner issue and it seems to not smoke at warm idle but I apparently "messed up" something else as the motor bogs and cuts down within a second after WOT.

Are the idle mixture screws THAT sensitive that I have altered the boat's performance? I had them 1.5 turns out each. When I mess with them at idle, not getting that much of a change in engine behaivior now.

Every time I use or touch this boat, something else goes wrong.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,277
Re: Officially Hate my Sport Jet 120 Motor

Sounds like the price was right though.
 

tech 3

Cadet
Joined
Jul 8, 2013
Messages
21
Re: Officially Hate my Sport Jet 120 Motor

have you checked your timming at wot
 

Frsmith2

Cadet
Joined
Jun 24, 2012
Messages
25
Re: Officially Hate my Sport Jet 120 Motor

Actually, no. One of the few things I haven't done. I just can't come to think that the timing just "randomly" went out of adjustment by messing with the enrichner and carb idle mixture screws?

Although with this boat it wouldn't surprise me if I changed a light bulb up front the ride plate would blow off...

The dying at WOT is different this time. When it was my fuel pump, it would die after a few seconds of getting on a plane (drained the bowls). They'd catch up, plane for a second, die again.

This time, revs go up for a bit but lacks power. Almost like its still in neutral at WOT where it still moves forward a bit. Then dies very quickly.

Back to the drawing board...which this time, I'll check idle timing and WOT (or crank).
 

tech 3

Cadet
Joined
Jul 8, 2013
Messages
21
Re: Officially Hate my Sport Jet 120 Motor

I cant see how the timing would jump but mide as well check it and get that out of the way
It sounds like a fueling problem
I am wondering if the auto enrichment plays a part in fueling other than start up's
 
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