First I want to say any ideas on this subject will be helpful and appreciated. First I have a 1997 seadoo speedster. Twin 720 engines. I got the boat last summer from Florida (not takes care of and eat up with salt water.) last summer I replaced all the cables, had both carbs rebuilt, flushed everything, and hit the water for a short period of time. My port engine quit running and after alot of testing and swapping from the running engine I found the stator went out. After replacing the boat ran great. At this time I also changed the carbon seal. This summer I ran the boat one time and due to salt water destroying orings water got on the piston and put a hole in it on the port engine. I took the engine to a local dealer and the told me just do a top end rebuild. While they were rebuilding I trimmed the plug wires. When I got the engine back and installed it, it wouldn't crank. I have 135 pounds of compression, strong fire, the plugs are getting fuel because I can pull them back out and smell it, but I am not getting the engine to crank. The battery is good, fuel is good because I can fire the starboard engine right up. I checked the mpem and had little corrosion on the grounds, cleaned it up, and still the boat won't run. Also the boat had the oil injection bypassed before I got it so I am pre mixing 40 to 1. If anyone knows where a complete oil injection system is I am interested in it also. Please help me get my boat running. I know basics as i am an auto mechanic and there are no seadoo dealers in my area. Thanks again for any advice you provide.
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Help please!!!!!
- Thread starter Joshp256
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The spark is strong. I pulled the plugs, hooked up the wires, and grounded it on a head bolt and there is clearly a strong spark. I true squirting gas, and a small amount of starting fluid at one point, and it won't try to run at all. I thought maybe the shop that rebuilt the top end had the timing off for some reason, though it shouldn't have been messed with on a top end rebuild. Correct? I called the shop and they confirmed to me they didn't touch the rotary valve or stator, nor remove the stator cover or intake.
This one is confusing as you state that you have spark and fuel.
Either the spark is at the wrong time (as in the timing is off) or you have a compression issue.
You stated the compression is 135 psi.
All of this makes me think it is a timing issue as you KNOW you have spark fuel and compression.
Try cutting the spark plugs a bit as they fail at the ends.
Either the spark is at the wrong time (as in the timing is off) or you have a compression issue.
You stated the compression is 135 psi.
All of this makes me think it is a timing issue as you KNOW you have spark fuel and compression.
Try cutting the spark plugs a bit as they fail at the ends.
jhjesse
Well-Known Member
JMHO,
Rotary valve timing is off. Need to pull the carb and RV cover off and check/reset. With engine installed in the boat, you will need a mirror.
http://www.seadooforum.com/showthread.php?9724-rotoryvalve-timing-mark-gti-720-help
http://www.youtube.com/watch?v=ULL5gfQs_UA
Hope this helps.
Rotary valve timing is off. Need to pull the carb and RV cover off and check/reset. With engine installed in the boat, you will need a mirror.
http://www.seadooforum.com/showthread.php?9724-rotoryvalve-timing-mark-gti-720-help
http://www.youtube.com/watch?v=ULL5gfQs_UA
Hope this helps.
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