i have a 23hp lomgtail that i just got.. when the prop is out of the water it will turn 4000 rpms but as soon as i drop it in the water it drops down to 1800.. also eveytime i turn the key the starter engages but as soon as the bindex hits the fly wheel it stops turning and wont turn the engine over... any suggestions???

SOunds like a bad starter solenoid?

1. load test battery if battery checks good, double check all your connections to ensure they are clean and tight, especially your grounds!

2. have you pulled your spark plugs out and inspected them? do they look old and black sooted or are they wet and smell like un burnt fuel?
2a - if plugs are old and sooted replace and see if you get spark on both cylinders.
2b. if wet, possible fuel delivery issue start by cleaning carb.

3. double check all fuel lines connections are tight and not allowing air to enter fuel lines.

Must be a backwater. If so, Sell it and get a Godevil.


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the may thing you should take away from inspecting your sprakplugs is do they look even? even wear, soot, ect. If they aren't "even" it can narrow your search to a cylinder.

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I have an 18 & 23 Vanguard (assuming that is engine we are discussing) in equipment not MMs, and they always look pretty close to "even" - I have been wrong before many times so it wont be the first time and my feelings wont be hurt if corrected