951 Carb Help

[mikidymac]

I finally got to take my 2001 XP out yesterday that I rebuilt the entire front engine mount on and it was fast. I rebuilt both carbs with genuine Mikuni parts and have done a lot of these carbs before so pop off was checked and they held 10 psi when finished. New fuel lines, oil lines filters and on/off valve.

It has 130 psi in each hole and turns 6800-7000 rpm wide open. It starts with choke when cold and on the first crank when hot without touching the gas and idles at 1400 rpm in the water and 3000 out of the water and runs great with no hesitation anywhere.

The issue I am having is when you sit for a minute or two with it off and then start it it fires instantly without throttle but as soon as you go to take off and give it gas it wants to die but as soon as you feather the throttle and get it past this it will not do it again until the next time you let is sit. Even long idling will not do it.

The other thing it does is when you come to an idle the idle will hang at about 2,000 rpm then slowly drop back to 1,400 rpm after a 10 seconds or so. I tried bliping the throttle to see if it was hanging up but id didn't make a difference.

I am going to pull the carbs back off but just checking to see if anybody had any experience with these issues to point me in the correct direction.

 

[donkey]

mine was doin that exact same thing for a while.while it was doing the "hangin idle" thing,it would also run away if started out of water! I found a bad seal at the reed cage,,fixed it all.i found it with the smoke tester at work btw.(used at work for testing for evap systems leaks on cars n such.)

 

[mikidymac]

Thanks Donkey, I was starting to suspect that.
I had planned to do a leakdown test on the engine when it was out but never got around to it. Looks like it might be coming out again.

 

[mikidymac]

Any thoughts on this Squirrel?

 

[racerxxx]

Any thoughts on this Squirrel?

I'll let you know his response:

Go buy new carbs from osdparts.com and sell your old ones on eBay.

Sent from my SGH-T889 using Tapatalk

 

[mikidymac]

I'll let you know his response:

Go buy new carbs from osdparts.com and sell your old ones on eBay.

Sent from my SGH-T889 using Tapatalk

HaHa, LOL. I did that for my GTI but don't want to spend that much yet if I can avoid it.

 

[donkey]

starting at 439.00,,,i dont have that much in most of my skis!
miki,another way to find a leak(be carefull,so u dont blow sh*t up) is to have it running in water on a trailer n spray a hydrocarbon in spots u think might be a leak,,carb cleaner works,but isnt totally accurate,because the fumes/liquid move alot,propane from an unlit torch with a small tube can pin point leaks.as u go past a leak,the rpms will go up.but,if u have a buddy at a car repair shop,use a smoke tester,i pulled the spark plugs,stuff the smoke hose in the hole(sealed good with rubber grommet) and watched for smoke.do both cylinders.i found my leak in about 15 seconds.after the 4months of scratchin my head.

 

[mikidymac]

Thanks Donkey,
I have all the equipment to do a leak down but got in a hurry. I know, I should know better. I think it might actually be carburation but I think I am going to pull the engine and do the leak down and check the carbs. I am the kind that will just keep thinking about it every time I ride it if I don't. I will report back.

 

[purple_people_eater]

x2 on the reed cages. might even be time for some new reeds.

 

[mikidymac]

At this point I have so little into this ski other than a lot of hours I would not even have a problem rebuilding it. The plan was mainly to make sure it would run as I was never able to fire it until now and it ran so good except for the small issues described above I was just going to run it this summer. If I find it need more than reed block gaskets it is getting a full rebuild with OEM parts.
This is one of those skis I always wanted and will keep so even if all in I am up to $1500 I am still happy.

 

[purple_people_eater]

If you wanna get a little wild with it, my buddy just found all his porting specs from when he used to race 951s back in the day. Some reed. Tunnel porting, cylinder porting, a set of single ring racing pistons and an aftermarket pipe and you'd have a 4tec killer lol.

 

[mikidymac]

Thanks Purple. My days of tuning and performance are done. All I want to do is add fuel and enjoy for the weekend with my 5 year old co-pilot without drama.