99 GTX Ltd 951...lacks acceleration/power

[SippiDoo]

Just purchased 99 GTX Ltd 951. Previous owner said ran fine about year and a half ago, been sitting since then. I put new battery, changed plugs, drained and put new gas. Have since also pulled RAVE's. carbon buildup was heavy, cleaned and everything else looked fine. Cranks and idles with no issues, but can only muster about 3580rpm. There have been times where it jumps up to about 7000rpm at which time I stay on the gas for about 30 min. After letting off of throttle it can only get back to about 3580rpm. The ski never stalls or dies. Any suggestions would be greatly appreciated. Oh yeah....ski has 160hrs

 

[SippiDoo]

From what I've been reading here its posssibly a fuel/carb issue. Where online is the best place to buy fuel filters and carb rebuild kits? Is it the 46i?

 

[- BiRkS_]

The regular top guys here will chime in soon, but first, take a compression test of your engine and see how your top end is.
Then pull the plugs and look at them. Mostly the ceramic insulators.Are they brown? black? white? You want a healthy brown-light brown colour. Black=fouled too much fuel. White=BAD, running lean. Is the ski hard to start? that would point towards a lean condition. When it only goes up to 3800 rpm does it sound like a bog sound or does it missfire and hesitate?

If the ski has the grey tempo fuel lines, go ahead and change them, clean the fuel selector and pull the carbs and clean them out, because you'll have to do it sooner or later.

 

[jhjesse]

Compression test first
Should be 130 - 135psi
Anything below 120 is rebuild time.

If compression is good crank it up on the hose rev to 5000rpm and check across the battery with a volt meter. Should read 12.6 to 13.5 volts. If not, your ski is most probably in limp mode and you need a voltage regulator.

 

[SippiDoo]

Thanks...it sounds like a bog at 3580rpm...one plug is white and the other brown...

 

[jhjesse]

Thanks...it sounds like a bog at 3580rpm...one plug is white and the other brown...

Pretty sure in only runs on one cylinder in limp mode.

 

[smc0922]

951 carb skis have limp mode? Ill be damned.....

I guess I need to crack open the service manual on this big block, I have a few more things to learn....

 

[SippiDoo]

Yeah...I'm not finding anything on the limp mode for the 99gtx ltd

I'll do a compression test tomorrow and hopefully just the carb rebuild kits

 

[SabrToothSqrl]

No such thing as limp mode on this ski. Your problem is fuel related.

Most likely dirty carbs/fuel line issue. 7k at WOT is fine for those hours.

DO NOT remove the exhaust pipe to remove the carbs. It is not necessary.

 

[SippiDoo]

Another question...the specs say a BN carb, but on the rebuild kits I'm seeing a SBN1. Is there a difference?

 

[SippiDoo]

Compression was a little over 130 one each cylinder....still need help as to which carb rebuild kit to get

 

[LouDoo]

According to the parts manual they are BN461.

http://fiche.seadoowarehouse.com/se...&make=seadoopwc&a=187&b=17&c=0&d=-CARBURETORS

Lou

 

[Minnetonka4me]

Take the carbs off and before you dig into them take the reed valves out. I bet you are missing a big chunk on one.

 

[SippiDoo]

Update.....replaced fuel lines, rebuilt carbs and replaced wear ring.....been out on the water the past two weekends and it runs great, no problems what so ever. I will say that getting those carbs off was a b***h! Thanks for all the advice.

 

[SabrToothSqrl]

you get used to it, i can pull 951 carbs blindfolded

glad we could help

I'll warn you now, the 951 runs (on average) 200 hours before it's service life is up... and it goes pop. No reason to panic, but when it does, you will have to rebuild the whole engine. some run 150, some run 300. some run 50.



make sure to use the 'correct' oil in the 951 as well. I am NOT starting an oil debate here (for the love of god), but this engine will fail if you do not do what the manual states for oil. I personally run XPS-II, however there are other oils that meet the requirements.