diagnosing poor idle- Idle bypass valve?

[Blue-doo155]

Have an 04 Sportster 155 w/ 50 hours. Bought this boat this past fall and only had a chance to run it once(for about an hour) Idle was/is poor (up & down rpms). Idle did start to smooth out a bit as I had it out on the water after a half hour or so. But if i go out and start it now, back to a poor idle. Other than that, it ran great. Had good throttle response up at speed. No dash lights on currently.. I did some research and it seems it could possibly be a gummed up fuel injector or an idle bypass valve? AT $200+ it would be an expensive guess. Any way to test my current bypass valve?
thanks!

 

[beerdart]

Start with new plugs and check the coils.

 

[Blue-doo155]

forgot to mention, drained & put in new gas, new spark plugs. Will check coils

 

[Blue-doo155]

coils seem ok..i'm going to order replacements anyway.. A replacement idle bypass is $200+, however i noticed they have aftermarket ones on eBay for $35. Any reason I couldn't go aftermarket? It sucks to spend over 200 on a part that I don't know is bad or not and from what i've read there no real way to test them

 

[pete63]

sure why not
by poor idle what do you mean? stalling, coughing or rpm hunting?
at idle 4tec's vary up & down 200 - 400 rpm.

 

[Blue-doo155]

when starting cold, it sputters out a couple times. after 2 or 3 restarts, it starts and runs with a wavy idle(for lack of better words). continuous up & down rpm's. After running 3-4 min and warms up, idle starts smoothing out. Don't have any issues up at mid- high speeds, Seems to run great. Again, I've only had a chance to run it on the lake once. Frozen now.. Im trying to get it taken care of now because if i 'have' to bring it to a dealer in the spring, i won't see it back for months on end. I'm going to post a short video when i get a chance. thanks

 

[pete63]

here some tips from the manual. they all mean either dealer or candoo system for checking or resetting.
check the throttle cable isn't to tight. might also need tps reset.

 

[Blue-doo155]

had my mechanic check this out. starts right up now, but idle is a bit rough when cold. Throttle cable is good, engine has good spark & compression. He ran boat and also noted that idle improves when warm. He thinks a partially clogged injector. He recommended to send injectors out to be cleaned and tested @ $240 for all 3. Seems a little steep. What do you think? spend the money or just run it?

 

[rcguy]

Isn't there injector cleaner you could add to the gasoline to clean the injectors. I don't know if this works but it is worth a try before spending $240. Try this link: 5 Best Fuel Injector Cleaners of 217 (And Why They Work)

 

[ID62]

You can clean the injectors for yourself. Search in YouTube for "seadoo 4-tec injector cleaning" ;-)

 

[Blue-doo155]

thanks, but couldn't find that seadoo-specific video. I found a replacement set (2 year warranty) of remanufactured injectors on eBay that have been cleaned & flow/pattern tested with new o-rings. For only $100 (all 3), i think thats way to go... According to the manual though, your supposed to hook up to buds to relieve the fuel pressure before removing fuel rail. Any way around this? Does anything need to be reset after installing new injectors such as the tps or anything along those lines? I'm really really trying to avoid another trip to the shop. Everytime i go it ends up costing a small fortunate so i'd like to tackle this myself

 

[ID62]

The pressure at the fuel system isn't very high. It's somewhere at 45 psi. Easiest way to release the pressure without BUDS is to wrap a towel around the fuel hose at the quick fastener at the pump outlet. When you pull this quick fastener back you can disconnect the hose from the pump and the pressure releases. Have a small cup or bucket nearby to let the rest of the fuel rinse out the hose. After this you can un-tighten the 2 screws from the fuel rail and then pull the it out with all 3 injectors. The injectors are fixed with a clip to the fuel rail. Very simple system. Just take care that you don't connect the DESS while the hose is removed because the pump starts running to get the system pressurized. After the change just connect the DESS and that's it. No further work is necessary. Before you mount the fuel rail into the air intake manifold pressurizes the system just to check if the injectors aren't leaking. Mine did this and it was hard to start the engine.

 

[Blue-doo155]

thanks for the tips! I got the new injectors in. easy. Still have this "pulsating" idle though. Going to try an aftermarket idle bypass valve @ $30 instead of the $200 stock one. If that doesn't do it, i'll live with it. It seems to smooth out after a minute or 2 anyway. I'm itching to get back in the water to see how it runs but still have this damn ice in the way

 

[IDoSeaDoo]

Any update on whether that idle bypass valve fixed it? I (and pretty much everyone with an older 4tec) have this problem. So far, nobody has ever found a solution. One guy claimed it was one of his coils, but that's like the fuel injectors, another expensive guess...

 

[Maroon5]

There are many injector cleaner you could add to the gasoline to clean the injectors. I don't know if this works but it is worth a try before spending $250+.

 

[Maroon5]

There are many things you have to check now. A replacement idle bypass is $200+, however i noticed they have aftermarket ones on eBay for $35. Any reason I couldn't go aftermarket? It sucks to spend over 200 on a part that I don't know is bad or not and from what i've read there no real way to test them

 

[Maroon5]

Have a small cup or bucket nearby to let the rest of the fuel rinse out the hose. After this you can un-tighten the 2 screws from the fuel rail and then pull the it out with all 3 injectors
Here I found something for you

 

[Maroon5]

There are many injector cleaner you could add to the gasoline to clean the injectors. I don't know if this works but it is worth a try before spending $250+.

check here I found something for you : Fuel Injector Cleaners