2000 seadoo Sportster LE Issues

[DavidR.]

Having all kinds of issues on my to 2000 seadoo sportster le
Dies when you give it throttle
Rebuilt carbs over the Winter
Compression 90 psi each cylinder
Any help would be appreciated

 

[Dr Honda]

That engine will never run at 90 psi. You may want to verify the compression gauge.

 

[DavidR.]

I will do that thank you

 

[Sportster-2001-951C-Stock]

Yep, it's doubtful that's enough compression but 90psi actually IS normal for some 2-stroke outboards.

I'm pretty sure you've still got carb issues, I went round and round on my 951 carbs myself. But at least confirm the accelerator pump and both nozzles are working (mine were fine).

Pressure check fuel lines to not more than 5psi and make sure there are no leaks else fuel pump will suck air instead of fuel. Sometimes the fuel shutoff/ reserve valves can be plugged with debris, restricting fuel flow when you need it most, so confirm fuel flow (temporarily bypassing fuel reserve valve is one way).

 

[Dr Honda]

Yep, it's doubtful that's enough compression but 90psi actually IS normal for some 2-stroke outboards.

Sure... a low compression engine can run at 90 psi. But that's it's design pressure. But his 951 was designed to run at 135 psi static compression. SO... if it's really at 90 psi... there is so much blow-by past the rings... it won't run properly. That blow-by will displace oil, and change the pressure in the lower half... in turn, displacing the fresh charge trying to come in.

I'm pretty sure you've still got carb issues, I went round and round on my 951 carbs myself. But at least confirm the accelerator pump and both nozzles are working (mine were fine).

My gut feel is that there is a fuel problem, and his gauge is just wrong. But until we verify... there's no reason to chase any other potential issues.

 

[DavidR.]

New compression reading on a different gauge 105PSI Each cylinder

 

[DavidR.]

Have not had time to check fuel pressure

 

[Sportster-2001-951C-Stock]

105 is pretty low, hopefully it improves but unlikely. You're(ve) reaching the point where power will be down and risking melting a piston (b/c heat from piston is normally absorbed into cylinder walls through oil film and tight tolerance). High tolerance from wear impedes flow of heat into cylinder walls.

It's probably best to rebuild at this point as opposed to risking a crankcase grenade. See if you can get a look at the piston skirts through the RAVE exhaust valve ports (remove rave valves) and look for piston scoring or gummed/coked rings. If you're really lucky and the rings are just gummed/coked, some evinrude/johnson outboard engine tune solvent might loosen that up but the compression needs to be higher, if possible.

If the gauge came from harbor freight then make sure the schraeder check valve is in the cylinder end of the hose and not the gauge end, as some were that read wrong out of the box.

 

[Sportster-2001-951C-Stock]

Sure... a low compression engine can run at 90 psi. But that's it's design pressure. But his 951 was designed to run at 135 psi static compression. SO... if it's really at 90 psi... there is so much blow-by past the rings... it won't run properly. That blow-by will displace oil, and change the pressure in the lower half... in turn, displacing the fresh charge trying to come in.




My gut feel is that there is a fuel problem, and his gauge is just wrong. But until we verify... there's no reason to chase any other potential issues.

My feeling is his gauge may be correct and at 90psi unfortunately it's rebuild time. Also persistent carb issues may have been the root cause of piston damage as often is the case, or just it's got too many hours on it and it's worn out. Running a 2-stroke lean leads to piston damage.