Some questions about 97 GTI

[Legacy37]

I have a pair of 97 GTI’s. I have some questions as these are the first pwc’s I have ever owned. Coming off idle to accelerate, they will hesitate and stall if you don’t feather the throttle to get the rpm up....after that they run great, they will only do 40 but that may be an impeller issue, I replaced both pump liners as they were damaged by rope when I got them. After riding for a while if you shut them iff they are hard to start...a few shots of primer and they will get going, don’t think this is normal so I am guessing carbs need rebuilding. Compression is 140psi in all 4 cylinders new plugs. Also the previous owner had the oil injection disabled (professionally supposedly) is there a write up for bringing that back up online? I really dislike premixing

thanks all! My kids love these things and I want to make them 100%

 

[dr00andrew]

first off did you rebuild the carburetors with genuine mikuni parts? secondly you could have a bad fuel selector switch and your fuel/water separator could need replacing as well. after you rebuild your carburetors check out this website and verify you have the correct settings/jets in your carb. your 97 gti should have a 175 main, 67.5 pilot and a 1.5 size needle and seat. im not sure what your pop-off needs to be but it should be around 35 or so, perhaps someone else can help you out.

your compression is good, so you have nothing to worry about in that instance. second off, it is not that hard to put the oil pump back on. you need to line up the marks on the pump to your cable at idle. after they are aligned you need to attach the oil feed hose to there and your oil lines from the pump to the block. with a cordless drill, take the plastic oil pump fitting and run it in reverse to prime the lines. after the lines are full of oil, loosen the bleed screw until all the air is out of the lines. your lines are good to go and primed. if you are on facebook, the user etemplet on this site has a couple of really good videos in a private group on fb demonstrating this. get in contact with him and he can walk you through it.

post some progress of your work and feel free to reach out with any questions. i have heard those 97 gtis are some of the most reliable 2 strokes seadoo ever made, you have some good skis and with a little work you will enjoy them for years to come

 

[Legacy37]

Thanks! I haven’t rebuilt the carbs yet...but I found the walk through on this site and will get the mikuni kits. These thing run great other than what is mentioned and they don’t burn much fuel...even better

 

[dr00andrew]

You are probably good on the fuel selector switch and water/fuel separator but if you are still having issues after rebuilding the carbs, thats your next step. Also make sure all of your fuel lines have been replaced to black automtive fuel lines and not the grey tempo ones

These are the marks of which i am referring to on the oil pump. this is what it should look like at idle.

 

[Legacy37]

Is there any particular brand or type of fuel line that is best?

 

[dr00andrew]

Is there any particular brand or type of fuel line that is best?

just go to your local auto parts store and grab 1/4" fuel line. you just dont want to use those grey lines as the ethanol in fuel breaks down the inner lining of them and clogs up your carbs

 

[Legacy37]

Rebuilt one of the carbs....it was popping off at 18 psi. After rebuild 30 psi. Looked really clean inside so that is a plus. I am not finding anything that looks like the oil pump linkage...I am guessing it was removed? Here is a pic from under the carb

 

[dr00andrew]

Rebuilt one of the carbs....it was popping off at 18 psi. After rebuild 30 psi. Looked really clean inside so that is a plus. I am not finding anything that looks like the oil pump linkage...I am guessing it was removed? Here is a pic from under the carb View attachment 49700

yes it is removed. i would recommend going back to the oil pump. i initially blocked mine off, but several users on here talked me back into adding the pump. the biggest reason is this. the pump delivers oil based on rpms (why its linked up to the throttle) at idle your mixture is 100:1 and about 32:1 WOT. it is also much easier filling up gas on the water when you have the oil pump. no need to worry about premixing. just add gas into the tank and oil into its reservoir

 

[Legacy37]

Where do I get the parts to reinstall it?

 

[dr00andrew]

should be able to find the oil pump on ebay. you will also need new 3/32 tygon oil lines

 

[Legacy37]

Is the 96 gti the same as 97? Found several oil pumps off 96s

nevermind, got the answer....pumps and line on the way

 

[Legacy37]

The carb pop off pressure was low on both carbs, I have it set to 32 now. Still have a hesitation when I floor it from idle to wide open....I suspect it’s going lean as it isn’t smoking. Is there a better way to tune these other than spark plug read?

 

[POPPS]

When I am chasing a lean situation...(with no gray fuel lines), I run the in fuel line directly from the pick up into the carb,,,if that clears your problem, you can go backwards to find the problem, If it doesn't, then the problem will be in the carbs....also,,,and easily overlooked,,,I like to take the in fuel line off at the pick up and gently with my mouth blow air into It,,,there is a mesh filter at the bottom that one in a hundred can become clogged,,,I also therefore blow into the reserve side as well...
Also check for kinked fuel lines near the water separator,,,sometimes when the gray lines are replaced,,,it's easy to kink the one line going into the separator...

When you have a hard starting issue on a hot engine,,,it can be that your rotary valve clearance is too much, and this will affect your primary compression,,,many moons ago...I went thru 2 starters,,,at the dealer,,,before a seasoned world champion racer,,,suggested that could be my problem,,,best $50 bucks back then I ever spent....the shop manual explains well how to measure the clearance.
Usually on stock boats the pop off is fairly high,,,pop off pressures usually maintain their psi' over the years..For race boats,,,I measure pop off,,,on stock boats I never have,,,only to see if the needle and seat are leaking,,,but this only gives a rich condition.,,,which you are not chasing...
Hope this helps.

 

[Legacy37]

went and ran them today. One needed a small idle adjustment and only had a very slight hesitation when going from idle to w.O.t. The other still has the serious hesitation and will stall and shut off if the throttle is not feathered. I don’t think its a fuel to the carb issue as it runs great at WOT...its the transition from idle through midrange. Im not sure if its going rich or lean....it quit which leads me to believe lean. Would the low speed mixture affect this? Another dumb question as these are my first PWCs....how much cavitation is normal? I rebuilt the pump on one with a new wear ring, impeller looked good, when you gun it the rpms definitely outrun the acceleration...thanks for all the help, these things are awesome fun so I want to get them to 100%

 

[dr00andrew]

I had an almost identical problem on mine from off idle to 1/4 throttle with a lean hesitation. Just increase the size of your pilot jets and richen up your low speed screws. Its always better to go richer because its easier to spot a rich condition rather than lean. Go to where its too rich and lean out your low speed screws. If thats still too rich, go back down on pilot size. It may take some trial and error, but eventually you will get it dialed

 

[mikidymac]

No, don’t change your jetting.
You have a fuel problem. Either you carb isn’t correct or you are sucking air.
Always replace the fuel selectors and fuel strainer O-ring.

Also what carb springs did you use?
Did you replace the needles and seats?

 

[Legacy37]

No, don’t change your jetting.
You have a fuel problem. Either you carb isn’t correct or you are sucking air.
Always replace the fuel selectors and fuel strainer O-ring.

Also what carb springs did you use?
Did you replace the needles and seats?

did not change neesdles and seat...the mikuni kit I bought did not have them. Used the spring in the kit....unsure what weight. Popoff was at 32psi. Will get o rings on thee way

 

[Legacy37]

Is there a way to pressure test the fuel selector, strainer, etc? Waiting on parts, just windering

 

[mikidymac]

Your issue is not replacing the needles and seats and using the wrong spring.

 

[Legacy37]

Your issue is not replacing the needles and seats and using the wrong spring.

will get needles and seats.....and springs on the way. Mikuni is the only brand that will work from what i understand. The spring is wrong even though popoff is in spec? Asking so I can learn about this system....I have inly worked with float type carbs in the past

 

[mikidymac]

Yes, because seadoo gives such a large range on pop-off even the wrong spring can be within the "seadoo range". If you look at the actual Mikuni chart the pop-off is pretty specific.
Only use the correct spring for your ski.

 

[Legacy37]

Yes, because seadoo gives such a large range on pop-off even the wrong spring can be within the "seadoo range". If you look at the actual Mikuni chart the pop-off is pretty specific.
Only use the correct spring for your ski.

Thanks! 1.5 needle and seats and 65 gram springs ordered!..well trying to be ordered...having a problem finding oem mikunis in stock

 

[mikidymac]

Everywhere is in short supply of Mikuni parts at the moment.

 

[Legacy37]

I found some....it says mikuni...it better be for 28 bucks each

 

[dr00andrew]

I found some....it says mikuni...it better be for 28 bucks each

it will have a rectangle stamping with the size next to it on if its genuine. I have been ordering all my carb parts from NicheCycle on ebay, they have had everything I needed to order in stock and shipped it right away