95 Sea Doo XP, Starts out of water, wont start in the water

[nigelg]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

I have confirmed that the compression in the front is much less than that of the back. probably 1/3. So definately not within the 5% range.

Where can I find more information on a top end rebuild?

Should I take off the top I think it is eight bolts, and look. What should I look for?

Could the piston be bent?
Looking for a seal that is bad?

It could be running a bit rich as I noticed it having a little bit more smoke than normal, and yes the plugs had oil on them. (new plugs and battery as of three days ago)

But once again, starting out of the water on the trailer and flooring it, it purrs like a little kitten, sounds terrific. (of course only do this for 5 or 10 seconds)

Is there any sort of seals that could be hosed, that need to be replaced?

This is a stock ski. Although a friend put a new motor in for me 2 years ago and it has run great, except for the normal smaller problems that everyone has always helped me fix on here. It goes 50+ on smooth water, and is very jumpy and fun... ;) (The trim on this model always breaks, so we just set it manually as straight as possible with a slight angle downards about 3 degrees, that is another topic though) ;) It makes it great for jumping over boat wakes!

Any suggestions on the best way to proceed would be excellent. I am not a mechanic, but enjoy working on it. My brother and friend are mechanics, and could possibly help if the top end rebuild is fairly advanced.

Thanks,
Nigel

[ShawnXB]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

I have confirmed that the compression in the front is much less than that of the back. probably 1/3. So definately not within the 5% range.

Where can I find more information on a top end rebuild?

Should I take off the top I think it is eight bolts, and look. What should I look for?

Could the piston be bent?
Looking for a seal that is bad?

It could be running a bit rich as I noticed it having a little bit more smoke than normal, and yes the plugs had oil on them. (new plugs and battery as of three days ago)

But once again, starting out of the water on the trailer and flooring it, it purrs like a little kitten, sounds terrific. (of course only do this for 5 or 10 seconds)

Is there any sort of seals that could be hosed, that need to be replaced?

This is a stock ski. Although a friend put a new motor in for me 2 years ago and it has run great, except for the normal smaller problems that everyone has always helped me fix on here. It goes 50+ on smooth water, and is very jumpy and fun... ;) (The trim on this model always breaks, so we just set it manually as straight as possible with a slight angle downards about 3 degrees, that is another topic though) ;) It makes it great for jumping over boat wakes!

Any suggestions on the best way to proceed would be excellent. I am not a mechanic, but enjoy working on it. My brother and friend are mechanics, and could possibly help if the top end rebuild is fairly advanced.

Thanks,
Nigel

At 1/3 compression, I would say it's hosed. If there's no warranty on it then it does little harm to start breaking it down and take a look. There could be a lot wrong, there could be little wrong. My guess (for what it's worth) is that you will require a top end rebuild at the very *least*. Probably easiest for you to just go ahead and purchase an SBT rebuilt.

Otherwise, tear it down with a mechanic and start looking at it. But stop trying to run it. Could do more damage.

[Bill O'Neal2]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Shawn,
You do not want fuel cell foam in your tank unless you plan to put a new tank in about once a year.

[ShawnXB]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Shawn,
You do not want fuel cell foam in your tank unless you plan to put a new tank in about once a year.

Do you have any good news? :P

[Bill O'Neal1]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

A HUGE problem with internet forums is that people read posts and jump to the conclusion that something is good because others are doing it. Not always the case, as with fuel cell foam. Works great for racers. Breaks down to tiny particles after a few months and clogs up carbs, not so good for rec riders.

[nigelg]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Ok, a buddy tested compression for me, results: 140 in the back 20 in the front.

We are taking the engine top apart next week.

Are there certain things to look for?

He is a mechanic, so we should be able to replace certain parts as required.

Thanks,
Nigel

[Bill O'Neal1]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Tape off the lower cases BEFORE you remove the piston wrist pins to keep all of the little needle bearings from falling into the lower cases.

A guy came into my shop yesterday after just replacing his pistons. He wanted to know what all that tapping noise was when he fired up his motor. He was not too happy to hear he just ruined his new pistons and head.

[nigelg]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Ok, my buddy did the top end rebuild for me, we are now at 140 and 140, starts and purrs like a kitten. Our thoughts now, since we originally replaced this motor is maybe it is running a bit too lean. Although lending it to my friends and having them running it full speed while it ran out of gas, apparently may have caused the bad piston as well? However, we are thinking of increasing the fuel to air ratio? We have found to adjustments underneath each carb which seem to have little handles on them. Do these small little handles increase the fuel to air ratio? If so, which way do we turn them. We have the Sea Doo Manual but we could not find the section that describes which way to adjust? Also, does this sound like a good solution?

It is also recommended to mix extra oil in with the gas, one person even recommended up to 1/2 and 1/2, which I think would be extreme? I am thinking of just putting a few cups in there with the gas, what are your thoughts?

Have a super day, and thanks for all the help! There are still a few good days left out on Lake Sammamish washington, and I am looking at full body wet suits to extend the summer.

Thanks again for all the outstanding help I receive on this
board. With my sea doo now, I am no longer lending it to friends, the two times I have, one time the motor ended up needing to be replaced and the second time I had to perform this top end rebuild. I would recommend people with older Sea Doos to treat them as an old 60's car, very gently... :)

Regards,
Nigel

[Bill O'Neal1]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

No I do not recommed that you mess the fuel air ratio.

I recommend rebuilding the carbs and making sure that the entire fuel system is in good working condition, no clogged up internal fuel filters in the carbs or a clogged up fuel selector valve.

Anyone who rebuilds a top end and does not clean the carbs is a fool, IMO.

Sea Doo calibrated your carbs to run at any place you may use it, with the proper air/fuel ratio. How would your changing it make it better?

[gmerz]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Hi nilgelg, I have the exact same symptoms as you described(starts out of water but not in) my machine is a 1994 XP. My compression is at 120 psi both cylinders. I dont no if this is good or not. I usually get engine started with jet pump out of water on dock then launch myself in water and the machine seemes to be running perfectly, until I stop and have to restart in water. Again no start.
My question to you is: Did you manage to start your engine and have it run pefectly until you stopped it in water, before you did your rebuild. Or did your engine run like crap when it did start in water.
I have checked many things on my machine including cleaning carbs, rotary valve clearance, electrical, grounds, battery. Still haven't solved my problem. I am beggining to beleive it may be a compression issue. Any feedback would be greatly appreciated.

[Bill O'Neal2]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

You definately have a compression problem. It should be around 150 psi, not 120 psi.
This will cause the motor to be very hard to start.

[bull_dog998]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

hi Bill i have a 1997 seadoo xp 787 and it is all rebuilt. i can not get it to start i have checked comperision it is 150psi in each cellinder. i have rebuilt the stock carbs it is getting gas. i have checked the rv timing and checked the rotory valve cover it is all oky. i have a new starter relay on it? battery is brand new could it be an eletrical problem i am getting spark don,t no if it is anuff though ? any help ????:emoticond

[SeaDood]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

pull off your rotary valve cover.if its scored with grooves in it that you can feel with a finger nail,then it needs to be resurfaced.i had this same problem on 2 of my skis,now both run great in an out of the water.
the factory clearance should be .010-.014 between valve and cover without the o-ring. depending on the damage there is a limit to how much you can cut the case whatever you remove from the case remove from where the cover bolts too to maintain the same depth.

[bull_dog998]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

i have now got a new rv and had got a new remachined rvc from sbt and now it is at the shop and has been for about a mounth now? he is doing all the work on it he said it is fireing now but still back fireing out the exhaust and through the rvc ?he said it is one or two thang,s one is he is checking to see if it is sparking in the right time ?and something about a valve ?any more help

[hydro X]

Re: 95 Sea Doo XP, Starts out of water, wont start in the water

Check the rectifier.