Low RPM in water, High RPM out

[saltydddog]

Newbie alert - but thanks for having me.

1999 GTX Limited, 240 hours, new owner this month. FIRST SEADOO!

I can only get 3200 RPM's while in the water, but as soon as we pull it out, it'll rev up to 6000 without any hesitation.

Easy diagnosis?

Thanks again for having this forum for help!

SaltyDDDog

 

[Dr Honda]

Well... sounds like the engine is on it's way out. (Out of the water doesn't count since there is no load on the engine)

I would start with a compression check. 150 is good... less than 130 is getting low.

 

[saltydddog]

Yikes. Thanks for the quick reply, I'll charge down this path. If anyone is interested, here a bit more information:

The engine has been modified to accept premix, bypassing the oil intake. Previous owner recommended 32-1, and I found that to run rather rich, since I was only going 20-25mph with the kiddos. Current tank is running 89 octane at 40-1. With 1/3 of the tank left, my troubles started, knocking, sputtering, loss of power, etc. Neighbor suggested I add some oil and after an additional 1/2 pint, I ran smoother, but the power is gone.

Have I just ruined the engine... gulp.

 

[Dr Honda]

More oil is not a "save" to a 2-stroke. Actually... it can cause damage. Extra oil will cause carbon build up, and can stick the rings, and your RAVE valves. 40:1 is recommended for a seadoo converted to pre-mix.

Speaking of oil... what kind were you using? Any of the seadoo's larger than an 800 need full synthetic API-TC oil. If you were using TC-w3 "Outboard engine" oil... that could be part of the problem.

Anyway... get those compression numbers, and we will go from there.

 

[saltydddog]

Penzoil Marine XLF (Extended Life) Synthetic.

Ugh.

Any chance using the right oil will help my problem, or is the damage done?

 

[ocod]

Penzoil Marine XLF (Extended Life) Synthetic.

Ugh.

Any chance using the right oil will help my problem, or is the damage done?

There is no magic potion to fix a 2 stroke.
Like Dr. said start w/compression check. Anything under 120 consider rebuild or at least take off head and look at piston and rings. Waste $300 now or spend $1k later your choice.

Report back with findings. If compression checks out your next step is the fuel system and jet pumps along with carbon seal.

all easily found in

http://www.seadooforum.com/forumdisplay.php?21-How-To-Tech-Articles

or for your rave valves.
(kudos to Rampage for his pic diy. Better than the last one)

http://www.seadooforum.com/showthread.php?37588-How-to-service-Rave-Valve-Pictorial


You should have your hands full with this...

 

[Dr Honda]

Penzoil Marine XLF (Extended Life) Synthetic.

Ugh.

Any chance using the right oil will help my problem, or is the damage done?

The damage is already done. The oil you posted is both a "Semi-Synthetic" and a TC-w3 oil. That oil can't suport the HP of your 951 engine.

There is no magic potion to fix a 2 stroke.
Like Dr. said start w/compression check. Anything under 120 consider rebuild or at least take off head and look at piston and rings. Waste $300 now or spend $1k later your choice.

Report back with findings...

Yep... what he said.

Get the compression, and we can give you your next step.

 

[JJinSC]

Oh yeah, and since you are running premix with the wrong kind of oil, I would recommend siphoning as much as you can out of your fuel tank.

 

[saltydddog]

Well this story *may* have a happy ending. I took the SD to a local mechanic known in these parts as 'the only guy to go to', who supposedly was also the maintenance man from the previous owner. When I told him my story this evening, including all of your concerns about compression, oil type, etc., he took one look at the engine and gave me some advice: He said my 'plugs are too cold'. Having been out of the water for over 24 hours, I thought - THIS GUY IS A GENIUS. What he meant was, the BR9ES plugs like to run hotter than my 20-25mph trolling with the kiddos. He said go pick up some BR8ES plugs and give that a try. He also highly recommended putting the kids on the beach after a few laps and let 'daddy play for a while' to keep the plugs clean.

Well a few hours later, after some cleaned valves (Props to RAMPAGE pictoral guide), and two new plugs, the SD fired right up and sounded much much better, and regained my missing power. It was after dark, so all I did was test it out near my private boat ramp, and didn't take it out for a full-lap spin.

I won't assume I'm fully out of the woods on this one - but the engine is giving me hope, so we'll see how tomorrow goes.

Cost of repair = $7.50 (two plugs and a can of carburator cleaner spray)

THanks for all the replies, I am very grateful.

SaltyDDDog

 

[ocod]

glad it worked out and only was 7.50

Word of advice always have extra plugs.