Donzi 120hp jet drive, engine issues

Jazman87

Recruit
Joined
Mar 28, 2016
Messages
1
Hello all, just joined. Used to frequent forums, but haven't in a while. If this issue has been brought up in the past, please give me a link to the thread, I really don't even know what to search for because its a specific issue.

Anyway, I bought this Donzi not long ago, ran great. Took it out today and the issues started. Boat fired up like usual, started to pull it to shore to let my wife in and it stalled out. From then on, starter would engage flywheel, but flywheel would just turn with no compression. I fought with it for about 45 mins at the ramp trying to figure out what was going on, and ended up putting it back on the trailer with my tail between my legs and taking her home. When I got home, I went ahead and hooked the hose up to it, and decided to see if the compression issue was still there. Wasn't... Now its turning over very slowly, like its struggling, as if there is too much compression, or battery is dying (its not, I checked the charge). I am mechanically inclined, but I don't know 2 strokes at all. Any advice to point me in a direction would be awesome! Thanks!
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
starter would engage flywheel, but flywheel would just turn with no compression
as if there is too much compression
while i'm no pro, i'd think a compression test would be in order. see which way it is, no compression or too much. find out what way it is and compare to specs for engine in question.
Now its turning over very slowly, like its struggling, as if there is too much compression
my first suspicion would be water intrusion into the combustion chamber. since water don't compress, that would make it turn over real slow.
after ya remove the spark plugs for your compression test. with the plugs out, rotate the engine over with the starter and see if it spits water out the spark plug hole. if water comes out the spark plug hole. you'll need to find out why its ingesting water and from where.
fyi. how a two stoke engine works.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
. When I got home, I went ahead and hooked the hose up to it, and decided to see if the compression issue was still there. Wasn't... Now its turning over very slowly, like its struggling, as if there is too much compression, or battery is dying (its not, I checked the charge). I am mechanically inclined, but I don't know 2 strokes at all. Any advice to point me in a direction would be awesome! Thanks!
I don't know what the original problem was, but it sounds like now you hydrolocked the motor.

If you turned the hose on before you started the engine you have a big problem. Pull the spark plugs and hit the starter. If water shoots out of the plug holes like a roman candle keep at it until no more water comes out. Then squirt some oil in the cylinders and repeat.

You need to get it running and then run the crap out of it to dry up the internals. You can't wait till this afternoon, you need to do it yesterday. Let her sit wet for a day or 2 and the engine will be toast.

I realize that getting it started may be easier said than done. Just be aware of the consequences. You might need a dealer to take it over.
 
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