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Exciter 270 issues

ryanv75

Active Member
Messages
3
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Boat Make
Yamaha
Year
1999
Boat Model
Exciter
Boat Length
17
Got a exciter 270 with a blown engine. Sent it away and installed - new engine runs great but shakes when accelerates. Seen where the impeller housing meets the hull and there is calking missing so I am pretty sure this is the issue with the shaking and the hull filling up with water. The other issue is with the old engine. It fouled a couple sets of plugs while the new engine didn’t. The new motor is on break in so the oil is pretty heavy at about 35/1. The old engine doesn’t start near as easily as the new one and the rpms would not hold steady it was dropping a couple hundred rpm here and there. Old engine didn’t want to start so I put new plugs in. The old ones has oil in them- on the new plugs the old engine only would get to 4000 rpm and then suddenly spring to life. By the end of the ride I couldn’t get it past 4000. Thinking it may still be a plug issue - I used NGK plugs. When I did a compression test of the old engine they looked ok and within about 5 lbs of each other. Just wondering if there are better plugs, if this could be a carb issue or if anyone has any other ideas. Also can you inspect the wear ring gap for the impeller without removing the whole assembly ?
 
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ryanv75

Active Member
Messages
3
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0
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Boat Make
Yamaha
Year
1999
Boat Model
Exciter
Boat Length
17
Also the throttle has to be quite a bit more advanced on the old motor to attain the same rpm - tack not working on new engine so I don’t know if it redlines but old engine tipped out at about 6000
 

ryanv75

Active Member
Messages
3
Reaction score
0
Points
30
Boat Make
Yamaha
Year
1999
Boat Model
Exciter
Boat Length
17
Here are some pictures of the calking on the hull, the impeller housing and the calking on the inside of the engine compartment was redone on the old engine side but not the new engine side
 

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4x15mph

Jetboaters Admiral
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Location
Downingtown, PA
Boat Make
Yamaha
Year
2018
Boat Model
AR
Boat Length
21
Sounds to me like a carb issue. Hard to beat sending them out and getting them professional restored. Unless you did this recently and really know how to test the pop-off, etc. I would consider doing this. I would also get some compression readings on both the old and new engine. The old engine may also be in need of a fresh, top end rebuild and it really isn't hard to do especially if the carb racks are already off. I did mine while the engine was still in the boat. I don't know if you have enough room in an exciter since my was an LS2000 but even still, these are lighter engines to move around
 
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