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Help for a newbie...

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cocacola

cocacola

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Howdy...
I am new to PWC, but not boating.
We have a 1997 Sea Doo GTI.
Good compression, fixed shaft seal and other basic maintenance including a carb rebuild.

My Sea Doo bogs and dies when I hit the throttle.
It idles and starts great.
I don't think the high speed circuit is kicking in....

Adjusted the low to 1 and high to 1-1/2...not sure where it is at this moment, but it's a lot richer but don't think it's right.

After all of this...I discovered "pop off pressure" and wondered would this have anything to do with it.
The kit came with 3 springs and should have just reinstalled the original.
I might start experimenting with other springs, but want to get on the water soon.

Tips or suggestions?

I have even thought of sending carb to someone to professionally rebuild and adjust.
If so....suggestions of who to send to?

Best regards
David
 
Which rebuild kit did you use? Is it a genuine Mikuni kit, or aftermarket? The aftermarket kits have some sub par parts included in them and cause problems 99% of the time.

Also, have you replaced all of the grey tempo fuel lines in the ski? If not, go ahead and replace them and your fuel selector before you dig any further into the carbs. You’re just going to plug the fresh carbs up if you run it on the grey lines.
 
Yes...the gray fuel line is long gone from last owner.
Aftermarket kit...

Where do I get a Mikuni kit?
Does the Mikuni kit come with several springs?
I am sure I neet to get pop off pressure right too...
thanks for replying Jeremy!
 
Osd parts sells different back to OEM carb kits. You shouldn't need multiple springs just the one that is designed for your ski. There is a thread on this forum for carb rebuilding that will take you thru the whole thing. If you follow it with a genuine mikuni kit you shouldn't have any issues. It's been a while since I went thru the carb rebuild thread but if I remember correctly it even points out how to tell if it doesnt have OEM parts installed.
 
You can also send your carb to the site sponsors PWC Muscle and they will inspect and rebuild with genuine parts.

I also suggest replacing either the entire fuel filter or at minimum the o-ring and also the fuel selector with new OEM ones.
 
Ok.....
Second water test only marginally better than first one.
We did have PWC Muscle rebuild the carb and that was probably it.

Starts fine on trailer and rev's like it should.

Starts fine on in the water but does NOT rev in water and dies before 1/2 throttle is achieved.

Then I started messing with mixture settings...no real difference.
NEVER COULD GET ON PLANE or rev like it does on trailer.

Another day lost.

One thing I have notice when running on hose or in the lake....water on top of the engine.
Not a lot, but there's no reason I can figure for it.
water around spark plugs threads too.
I have been looking at gaskets and o-rings to possibly replace, but first going to take head off to see.
Items 4, 5, 7 & 8 on picture.

My guess is water getting into cylinder(s).
Everytime it dies on the water, it easily restarts.
 

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why would there be water on top of engine?
I suspect o-rings around spark plug holes are leaking.
Would that short out plugs?
 
150 is perfect and 120 is done and ready for a rebuild and might not start int he water.

Your big issue is that they are uneven so we know one cylinder is going. You shouldn't have more than about 5 psi difference and you have 15.
 
No, it won't be.
You need to bore the cylinders to nhe next oversize and install the correct new pistons and rings.
 
I can't explain why there's water on exterior of engine but if water was in the cylinders it would be hard to start if that water reached the spark plugs they would not fire.
 
last night I pulled the water jacket and head....guess what? no o-ring's around spark plug cavity on water jacket.
cylinders have no detectable damage from my bare hands and visual.
the lower psi cylinder looks like the ring gap is slightly larger.
replacing...

the o-rings that seal head to cylinder looked good, but have flattened over the years plus the higher compression cylinder to head seal had a bad spot on it.
replacing

Pistons looked good.

Never did change spark plugs.
Replacing
 
Finally getting Seadoo back in water and Summer is almost over.

New plugs added after PWC Muscle carb rebuild.

I see so many needle settings online…



Mine are set at 1-1/2 low and 1 high.



One more thing….

I used to notice water weeping on top of engine. After removing water jacket, there were no o-rings around spark plug holes. I ordered a kit and changed all upper seals except for removing cylinder and doing base gasket.



Seadoo ran better than last time, but still bogs when giving full throttle.

Faster than before, but probably only 20mph but I could apply more throttle than before.

I read online where some guy slightly choked engine when running like this.

WHOW! It took off like a rocket, but soon died because I choked completely.

Tried it again about 1/3 choke and I was hauling butt….full speed.

Engine was screaming fast and I rode it a lot.

Not good to drive a PWC with one hand on the bars, so I limited this plus sought smoother water.

Then I pulled over to shore, adjusted choke cable and was running fast with 2 hands on the bars….lots of fun for sure.



Previous owner had removed stock air cleaner, so I am thinking that the less restrictive intake is making this thing run so lean and that’s why I have to apply some choke to give engine enough vacuum to draw more fuel into engine. How does that sound? It has a K&N style air filter.

I have noted another needle setting online of 1-3/4 on low….but it’s the closed setting on high that makes me suspicious.

Need input and suggestions.

I can ride it as is, but unsure of who things are set up.
 
Oh man, where to start... First, quit riding it like this! You’re lean, and continuing to ride it the way it is will seize the motor. Using the choke is only a test to see if it picks up, don’t ride it with the choke engaged for more than a second or two...

Second, your aftermarket flame arresters are causing your problem. Two strokes are not like auto engines where you can just throw a cold air intake on and be good to go. In order to use the K&N style filters, you will need to rejet the carbs and tune for the prober adjustment settings. If we had known you had those installed, we could have sorted this out immediately...

You’ve got two options here to be able to ride the ski and enjoy the rest of the summer. The first option, and the one I would highly recommend, is to find a stock airbox and flame arrestor, and pull the K&N’s off. This will allow you to use the stock carb settings and will supply more air than the motor can use anyway. The second option is to do some research and find out what jetting is recommended for your particular ski and that brand and model of filter. You’ll then have to change the jets in the carbs and use the plug chop method for finding the correct needle positions.
 
Also, the reason your compression is so uneven is because someone ran it with those filters and the stock carb settings. They’ve already started to seize one piston, hence your earlier readings...
 
I am new to PWC and didn't know all of this.
The first owner is a good friend...hopefully he still has air box.
If now...I've looked online.

Single carb engine.
 
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