'97 GTI sputtering after 1/2 throttle

[ground minnow]

I would first like to thank all the members on here, you have helped me so much up to this point!

Long post (sorry) but I need opinions. I bought a '97 GTI and it hadn't ran in 4-5 years. It takes a while to start but after it starts it runs great up to about half throttle. After that it starts sputtering and if I back it off to around half throttle or a little less it will run clean for as long as you want to run it. The compression on the mag side is 143 and PTO side is 140

The following is what I've done up to this point.
replace the oil lines on the automatic oiler Replaced the old gas lines
Replaced solenoid
Replaced coil (Amazon) this purchase was made before I found this site and realized there are quality part dealers out there
Replaced MPEM (Amazon) this purchase was made before I found this site and the reason for replacement was somebody stupid hooked positive and negative cables up backwards. It's me, I'm stupid
Rebuild carb (genuine mikuni) OSD back to stock

After the carb rebuild it held 10 psi for 45 minutes and the pop off was at 35 psi. It has stock jetting and LS and HS were 1turn and 1-1/2 turn. I made sure to follow the rebuild thread to the T and made sure all passages were open. Also the dental floss technique worked perfect for me. I have also tried running it by bypassing the on/off/reserve and hooking straight to the pickup on the reserve nipple.

I have check the voltage and it never gets above 14.2 volts. After running it for a few minutes I noticed that the top 5amp fuse was almost melted into the MPEM. I was able to free it up and it wasn't blown but it did replace it and put a little dielectric grease on it.

Also it has never beeped when the key is installed until today and it beeped twice and then fired up really quick. I rushed it to the lake to try it and in a 5 minute trip no beep when I got there and was a bear to get to crank.

Any help would be GREATLY appreciated.... Thank you so much for even reading this long post!

 

[burtshaver2021]

I would first like to thank all the members on here, you have helped me so much up to this point!

Long post (sorry) but I need opinions. I bought a '97 GTI and it hadn't ran in 4-5 years. It takes a while to start but after it starts it runs great up to about half throttle. After that it starts sputtering and if I back it off to around half throttle or a little less it will run clean for as long as you want to run it. The compression on the mag side is 143 and PTO side is 140

The following is what I've done up to this point.
replace the oil lines on the automatic oiler Replaced the old gas lines
Replaced solenoid
Replaced coil (Amazon) this purchase was made before I found this site and realized there are quality part dealers out there
Replaced MPEM (Amazon) this purchase was made before I found this site and the reason for replacement was somebody stupid hooked positive and negative cables up backwards. It's me, I'm stupid
Rebuild carb (genuine mikuni) OSD back to stock

After the carb rebuild it held 10 psi for 45 minutes and the pop off was at 35 psi. It has stock jetting and LS and HS were 1turn and 1-1/2 turn. I made sure to follow the rebuild thread to the T and made sure all passages were open. Also the dental floss technique worked perfect for me. I have also tried running it by bypassing the on/off/reserve and hooking straight to the pickup on the reserve nipple.

I have check the voltage and it never gets above 14.2 volts. After running it for a few minutes I noticed that the top 5amp fuse was almost melted into the MPEM. I was able to free it up and it wasn't blown but it did replace it and put a little dielectric grease on it.

Also it has never beeped when the key is installed until today and it beeped twice and then fired up really quick. I rushed it to the lake to try it and in a 5 minute trip no beep when I got there and was a bear to get to crank.

Any help would be GREATLY appreciated.... Thank you so much for even reading this long post!

It’s very possible those parts from Amazon May end up causing issues for you. There is a salvage yard thread I can attach if you like? Better off with good used OEM parts. A lot of people in here prefer West side powersports. Your low speed screw should be 1 3/4 out and high speed 0 turns out.

 

[ground minnow]

Thank you for your reply and help! Yes, if you wouldn't care would you please post that salvage yard site. Or I could quit being lazy and just look for it myself. I started buying parts before I found this site and had reservations about buying them while I was doing it. I will adjust the LS and HS when I get home tonight. I was meaning to call West Side PowerSports yesterday but life hit me in the face so I will try to reach out to them today.
Again, I thank you for your help!

 

[burtshaver2021]

Updated PWC used parts & Salvage Yards
Here is the thread with list of salvage yards. Your very welcome, good luck, hopefully you can get some enjoyment from the machine this season.

 

[burtshaver2021]

Just looking at one of your past posts and you mentioned hiking up the negative and positive backwards, do you mean the battery? I’ve not had issues with MPEM on seadoo’s but I did hook up the battery backwards on my Wet Jet Kraze and yes I felt the same way. After I did that I had nothing but there ended up being a fuse thankfully. Maybe you only popped a fuse and that old MPEM of yours is still good? Worth having a look at anyways. not sure if I mentioned it to you but you can get shop/service manual at
Seadoomanuals.net for free

 

[ground minnow]

Yes, I hooked the battery up wrong. I wish I could say this was only the 100th time I've did something dumb.

I did pop the top 5 amp fuse and I did replace it but I couldn't get it to run after that. That's when I bought the MPEM from Amazon.

It's weird because I had to leave it out on the trailer because I was caught in a severe thunderstorm and the next day the beeper started working and it fired up really quick. I'm going to re-check all connections when I get home and I might even throw the other MPEM on just for the heck of it.


I know it's a costly unit but I don't care to have to buy a proper MPEM for it. I really would just like to be able to take it out.

I really do thank you for your help and input with this.

 

[mikidymac]

For guaranteed and tested used parts Westside Powersports Seadoo @Minnetonka4me

 

[ground minnow]

Mikidymac I talked to Nick a little earlier and he has made a suggestion as to what my problem might be. Super cool guy. I'm on their website now but for the life of me I can't find the part. I'm looking for to order it. I used to think I was pretty good at technology but anymore I feel like an idiot.

Seems like this is a pretty cool community and everyone has been super awesome with their help.

 

[ground minnow]

It ended up being the crap coil I bought from Amazon. Nick at West Side PowerSports hooked me up. 99 out of 100 would have sold me the MPEM first and then the coil so thanks for looking out for me Nick!