1999 challenger 1800 tops out at 12mph

[BOOSTINTT]

so i bought a project challenger.
guy i bought it from said it ran great (in salt water) just needed maintenance
both engines have 150 psi in each cylinder.

first time i turned them on seemed as they were in WIDE OPEN THROTTLE

bought new carbs for each engine

first engine idled a lot better, the other engine did the same (WOT)

i swapped carbs again and they were not as bad.. but still seemed as if they were reving too much for idle.

i took it to the water... (lots of smoke but it kinda went away after a while)

loud beep which i would turn off by pressing the bottom right yellow button

the small black pressure valve on one of the engine was leaking a little bit of water from the bottom

i got the boat to do 12mph full throttle.

i did not really pay attention to the rpm or anything else other than my boat sinking (very new to boats)

I checked impellers, they move freely but WEAR RINGS are gone.. completely dried out.. could this be making my boat run like crap and top out at 12mph?

what else should i look into?

 

[Dr Honda]

Well... WOT isn't good. You need to look for an air leak.

If there is a large gap between the impeller, and the pump housing... then yes... that is a problem. BUT... I would also be looking at the carbon seals. (Driveshaft seals) When they are warn... then the boat doesn't go anywhere.

 

[BOOSTINTT]

again thanks DOC for the info.

yes there is a hughe gap between impeller and housing.. basically no wear ring. i will look into the carbon seals as well. at what end of the shaft do those seals go to?

Well... WOT isn't good. You need to look for an air leak.

If there is a large gap between the impeller, and the pump housing... then yes... that is a problem. BUT... I would also be looking at the carbon seals. (Driveshaft seals) When they are warn... then the boat doesn't go anywhere.

 

[ocod]

again thanks DOC for the info.

yes there is a hughe gap between impeller and housing.. basically no wear ring. i will look into the carbon seals as well. at what end of the shaft do those seals go to?

Its right after the pto where drive shaft is.
It has a rubber boot with graphite floating ring inside of it. It forms a seal with the SS ring.

Also boat rpm outside is ~3000 in the water is 1500

 

[DnE1800twin]

the cavitation from having no or worn wear ring will cause significant loss in speed. the engine will rev up and you'll go nowhere.
If you were able to swap carbs and a difference was made than it sounds lik you may need to adjust your carbs. start with factory settings that you can find here in Seadoo Forums for your particular model.
Also if your boats been running in salt water your exhaust regulators may need to be removed and cleaned. Checking for a clog and that all the water hoses are properly connected.
That carbon seal and the water cooling lines are the only entry way for water to fill your boat.... Unless you forgot to screw in your bilge plug.
Hook up the hose and turn it on just a little bit. you dont want to build pressure without the engine running but just enuff water in the lines should point out a leak.
Theres a ton of helpful ppl here in the forums... good luck

 

[BOOSTINTT]

finally got the new wear rings from SBT.. does anyone know if the little lip on the ring goes up or down when inserting it?

 

[BOOSTINTT]

i took it out just now and still nothing. gets up to about 12mph. rpms on both engines top out at about 4k. idles at 1200 rpms in water and 3k outside of the water. i installed new carbs and new wear rings on both sides.

even with the new wear rings (my old ones were completely destroyed) i couldnt get it to go faster than 12mph