03 Speedster Problem; Fine when cold then gets slower & slower & slower...bogs at FT

[swiftvision]

Yes, I am a newbie and a boat newbie at that.

I bought a 2003 Speedster with the Merc 240HP 2 Stroke V6 last winter. I had a local boat dealer do a full PPI and everything checked out perfect. The boat only had 100 hours on it. After I bought it I had the dealer do a full service and winterize. They changed all the fluids, both fuel filters, spark plugs, and treat the gas.

Come Summer I took the boat out for the first time to a lake in high elivation. The boat would only go to 4000rpm and about 39mph and then would slowly get slower. At full throttle it would bog down even more. I had to keep the thottle between 40-60%. Took the boat out and back to the dealer.

Dealer tested the boat in there tank, compression, etc....found nothing wrong.

Just took the boat out for the second time to test....this time at a sea level lake. Right off the bat the thing ran awesome, 6000rpm, 60mph and haulin in full throttle....then about 3 minutes in it starts getting slower and slower and slower. The RPM's and speed drop and full throttle bogs it down.

I stop the boat and we hang on the water, motor off, for about 40 minutes. Start it back up and blast off for about 1 minute with everything perfect (6k rpm, 60mph), then the same thing.....slower and slower. It drops from 60-35 in about 2 minutes time.

WTF is going on here!?!? I heard about problems with the exhaust pipes coming apart and plugging the flow but my dealer swears he looked at this????

Any advice?

 

[Dr Honda]

Could be overheating, or your high pressure fuel pump isn't happy.

As far as the dealer checking the pressure on the fuel pump... it may not show up since it runs OK for a while.

 

[swiftvision]

Are there any typical sensors which may fail related to heat? Is there any way to test the high pressure fuel pump without taking it to the dealer?

 

[swiftvision]

Oh my compression is 140PSI across all cylinders.

 

[Dr Honda]

140 is pretty dang good for these engines.


Yes... you can test your pressure. There is a schrader valve on the high pressure rail. Put a gauge on it, and start the engine. Better yet... go for a ride, and when it starts to die... check it then.

 

[swiftvision]

Think changing out the port side temp sensor may be wise? Seems to be a common failure. Is there a prefured online retailer for Seadoo parts? I can't seem to find part #13536A14 on google search.

 

[Dr Honda]

Think changing out the port side temp sensor may be wise? Seems to be a common failure. Is there a prefured online retailer for Seadoo parts? I can't seem to find part #13536A14 on google search.

Cant hurt... but generally when it goes bad... it runs rich at idle, and just burns a lot of extra fuel while running. The SB side sensor is the one for the over temp warning.