Need advice on 2000 GTX carb 951 model

[offgrididaho]

Bought a low compression (either 100ea cyl or 110 ea cyl , used 2 gauges) seadoo in great condition with a trailer in great condition for $900.
The trailer is worth 900 so I got a near new looking ski free. The clock shows 225hrs. I need advice on how to proceed. It was supposedly rebuilt and never ridden and I can see paint chips off head bolts but nothing else. Gray lines have been replaced. Not sure if carbs were rebuilt. Last reg tag is 2025.

Do I swap motors?
Do I use a wiseco top end and see how long it runs?
Where is a great place to buy a motor?
Do I rebuild it myself including crank?

Warranty is meaningless to me as I won't ever pull a second motor and install a third. TOO MUCH WORK! Im too old and have bad arthritis.
I need a motor that WILL BE 100% reliable and never need a warranty. I know its a lot to ask but I dont want junk!

 

[WhiskeyD]

Why not tear down the motor in it and inspect?

 

[offgrididaho]

?
To what end? I know the motor is bad.
Did you see the 4 questions I asked?

 

[shamrock246]

Can you bore scope the cylinders? Does it run?

Do you have a spare motor to swap out?
The bore sizing has to be done different for forged pistons vs cast (OEM)
Not sure of a good place to buy a rebuilt motor, I rebuilt my own.
I rebuilt mine (787), I had my crank rebuilt by Competitive Crankshafts on Facebook and a top end kit from River Rat Bob on eBay. GroupK is highly recommended for top ends.

 

[burtshaver2021]

?
To what end? I know the motor is bad.
Did you see the 4 questions I asked?

As mentioned above I think inspecting the motor would be you first step. Take it apart, measure your bores. You did mention it was just rebuilt? Have you tried starting it? It would be good for you to know what you have. Or if you don’t want to be bothered with that type of thing just buy a rebuilt moto and drop it in. Peter Rucinsky is who I would recommend. Can’t remember the business name but if you search his name you should be able to find him

 

[burtshaver2021]

Just read the last part of your original post, sounds like the best thing for you to do would be to tow the whole machine to someone and have them pull the engine and drop in a new one for you. Again Peter Rucinsky. Don’t get any blow Joe to do the work, I can tell you from experience that automotive mechanics don’t know these machines well enough to do the work properly. You need someone with plenty of experience with them

 

[offgrididaho]

It started and ran when i got it home. Too cold to put it in water. Compression is either 100 or 110 depending on which gauge is right. I think the head was off but see no signs of the rest of the motor being out or rebuilt. I think the rebuilt is BS. It would have only 5hrs since rebuilt and 100psi, nope! The rear cyl is leaking 1lb per second. The front is leaking 1lb per min.

What is the cost to get the crank rebuilt?
What does Fox charge to build a 951-carb model?
How much is a wiseco top end? (is that the best?)
Is there something better then wiseco?
Where do I get my cylinders bored .005 over?
Is that the size I want to go?
I do not have a way to measure anything precisely.

 

[burtshaver2021]

I would ensure that I have a good compression guage, you’ve already mentioned one gauge reads 100, another gauge reads 110, do you have a good strong battery in it? By the way, never ever boost it from a running vehicle. If you tested it cold numbers would be lower, on these 951’s 130 is perfect compression, the rings probably have not seated yet. I’m not saying the motor is good, and I definitely have no way of knowing if the crank was rebuilt or replaced but the fact it runs would entice me to investigate further. You may be replacing a perfectly good engine. I’ve never heard of doing a leak down test on a 2 stroke? I’ve heard of doing it on a 4 stroke engine but I’m far from an expert. Like to hear more about the cylinder leak down for a 2 stroke.
With that being said if your dead set on just replacing it. I don’t know the cost of a rebuilt crank, I would guess 800.00 ish. I don’t know what Fox Powersports charges to rebuild but I would call them, and if at all possible I would take the machine to them. They have a great reputation of standing behind there work and you don’t want to spend a fortune just to have it melt down due to an air leak.
Peter will bore them out, it will be a minimum of .010, (.25mm)
I would not use forged pistons, I’ve seen Pro X pistons thrown around on here, but definitely cast pistons.
At this point if your rebuilding, you just need to make some calls for pricing

 

[offgrididaho]

I would ensure that I have a good compression guage, you’ve already mentioned one gauge reads 100, another gauge reads 110, do you have a good strong battery in it? By the way, never ever boost it from a running vehicle. If you tested it cold numbers would be lower, on these 951’s 130 is perfect compression, the rings probably have not seated yet. I’m not saying the motor is good, and I definitely have no way of knowing if the crank was rebuilt or replaced but the fact it runs would entice me to investigate further. You may be replacing a perfectly good engine. I’ve never heard of doing a leak down test on a 2 stroke? I’ve heard of doing it on a 4 stroke engine but I’m far from an expert. Like to hear more about the cylinder leak down for a 2 stroke.
With that being said if your dead set on just replacing it. I don’t know the cost of a rebuilt crank, I would guess 800.00 ish. I don’t know what Fox Powersports charges to rebuild but I would call them, and if at all possible I would take the machine to them. They have a great reputation of standing behind there work and you don’t want to spend a fortune just to have it melt down due to an air leak.
Peter will bore them out, it will be a minimum of .010, (.25mm)
I would not use forged pistons, I’ve seen Pro X pistons thrown around on here, but definitely cast pistons.
At this point if your rebuilding, you just need to make some calls for pricing

OK, thanks. How do I get a known good gauge? I just rented 2 brand new gauges from 2 different auto parts stores.
How do I tear into the motor to see if everything is replaced and new? How do I know if carbs were rebuilt?
I dont have a bore scope nor can you rent one.
I dont have the fancy tools to measure a bore.
How much different is compression cold/hot, ive heard it maybe 5 lbs. I doubt its going up 30 psi. I tested another ski the other day and it had 143/170 COLD. Same ski, a GTX carb model, same guage.
I called Fox about a rebuild and its $1650 + aprox 200ea way for shipping. NO WARRANTY---->ZERO!
Called the Boise crank builder and he would rebuild my crank for 625 and parts for top end and bore each cyl was another 525 with 80ea way for ship.

 

[burtshaver2021]

You tested another 951 engine and it tested 143 and 170? Not sure what to tell you there except like I mentioned before 130 pounds is perfect on a 951, are you sure it wasn’t a 787 engine? Even then, that’s odd as perfect for those is 150 but could have been a leaking inner crank seal causing the high compression reading.
I personally wouldn’t tear into the motor if you don’t have any tools to measure the bores unless you can take them to someone who does, I had suggested tearing it down , I’m only suggesting you find a compression tester that is known to be accurate, maybe from a friend or family memeber that works on 2 strokes? Maybe a shop that works on them? Anyone that has one that has some 2 strokes and trusts there guage. My guage is cheap but I trust it.
Compression doesn’t need to go up 30 pounds, you said it tested at 110 per cylinder, perfect is 130, 115 to 120 is time to rebuild, you may be right about 5 more pounds if testing after running.
Good luck

 

[burtshaver2021]

Just thinking about your situation there and you’re probably correct in thinking it needs everything. I mean who has any engine completely rebuilt and then sells it 5 hours later for 900.00. With a trailer in mint condition.

 

[offgrididaho]

Just thinking about your situation there and you’re probably correct in thinking it needs everything. I mean who has any engine completely rebuilt and then sells it 5 hours later for 900.00. With a trailer in mint condition.

He got it from his Bro who said he had it rebuilt. He took it out last summer for maybe 5-10hrs. Said it ran poorly cold but ran good hot. Thought it was a fuel issue. Took it to another local shop who charged him 2600 to basically do nothing and not fix the problem. Bro#2 was fed up and just wanted it out of his driveway. I agree.

So normal psi per cyl is 130 and not 150?

 

[burtshaver2021]

He got it from his Bro who said he had it rebuilt. He took it out last summer for maybe 5-10hrs. Said it ran poorly cold but ran good hot. Thought it was a fuel issue. Took it to another local shop who charged him 2600 to basically do nothing and not fix the problem. Bro#2 was fed up and just wanted it out of his driveway. I agree.

So normal psi per cyl is 130 and not 150?

Yes, for 951 130 is perfect, all other Seadoo engines 787, 717, 657, 587 150 is perfect.

 

[offgrididaho]

Yes, for 951 130 is perfect, all other Seadoo engines 787, 717, 657, 587 150 is perfect.

Well crap. Maybe I pull the cyl and hone it with a new set of rings and see what happens. Who could measure the cyls for me, what type of shop?
What increase in psi will I see from 30-40F temps to running temperature?

 

[burtshaver2021]

Well crap. Maybe I pull the cyl and hone it with a new set of rings and see what happens. Who could measure the cyls for me, what type of shop?
What increase in psi will I see from 30-40F temps to running temperature?

I don’t recall ever seeing huge gains from cold to warm, maybe 3 pounds. Where I would have any hope is that if the previous owner did in fact rebuild it and the rings haven’t seated yet, could gain 5 or 6 pounds there.
It’s really hard to say what is going on, I’m only throwing crap at the wall but maybe they do rebuild it with forged pistons and that why it runs like crap when cold and good when hot? I don’t know
As for who can measure it, of course any performance shop, maybe a fabrication shop. I think the mitutoyo outside caliper I bought was maybe 200.00 Canadian roughly and the Fowler dial bore gauge maybe 100.00. Not worth purchasing though if your not going to be doing anymore work with them, but they are not crazy expensive