Dual 38 tuning advice

[tom21]

Its been so long since ive ridden and i have other skis that seem to have been neglected for over a decade. Time moves funny. Ive probably forgotten more than i remember other than how stuff goes together. And i wasn't that great at tuning before!

So, trying to fix up a second ski cause one of my kids actually will ride with me! Fricken finally!!!! As you would expect the motor was seized. Luckily i have a few motors that i pulled from running skis way back in the day. Somehow sitting outside vs in the ski a few of these were still not frozen. No history other than i know i drove them to the boat ramp when i picked em up. 15 years ago?

Freshened it all up, tank, fuel lines, ebox, chase down start stop gremlins, rebuilt carbs. Fought the protec pipe off the old motor(nightmare stuff). Wrestled it back on the donor. Fig im almost out of the woods now, i can just taste the salty air!!! Runs but barely, also discover the idle set screw is seized. Yay.

After going thru the carb database i upped the jetting. Was 130m 67.5p. 1.5 n&s w what i thought was a 115g spring. Looked like it. Popped at 50 though.

Switched to 132.5 and 72.5. ski started but would not rev up much. Kinda did a bub bub bub. Ok so swap in a 75 pilot. Same. Of course i tried running screws in and out. Still no noticeable change. Ran screws all the way in, backfire. Lol. Ok. Stupid.

135m 75p? Same. Something not right. Pull carbs, been changing jets in the hull, Go thru it again. Find a leak in the fuel pump. Swap in some 95 gram springs. Pretty sure these are from riva but now im thinking these are some crap ones. 95g springs pop at 60psi. Yep those are in the garbage. Found a bag from winderosa says 95g. Yay 43 on the nose! Looks like i found my problems! Bub bub bub. Sheeeet!

So recap, protec pipe
Stock motor
Dual 38s no chokes oem flame arrestor.
132.5m
75p
1.5 seat 95g spring 43 popoff
1 1/4low
1 1/2 hi

Is this a carb issue and i need to up the needle and seat or lower spring or is this maybe electrical?

The long buildup was to give what i have and what ive done. Hopefully it was a little funny cause we've all been there. Some of us on the daily! Ive seen a post or 2 that seemed like the same issue but didnt get resolved. With the knowledge here i doubt if somebody hasnt seen this before. I cant be that unlucky. I have another set of 38s i tore down and just need the valve bodies from. But being as the problem doesnt seem to be effected at all by any jetting, im feeling like it might be something else. Ebox was crusty, but when are they not? I cleaned it all and none of the connections were green. Just crud blooming in the box. Could this be a stator issue ? I dont know where to go next. I have quite a few parts i can swap but id hope that somebody will swagger in here and scold me for not knowing this is the most common problem ever and im an idiot for even asking such a newb question. Ill be happy to take any and all abuse, i just want to go ride w my boy! No telling how long this window of opportunity will last.

Please help a brother out.
Thanks

 

[WFO Speedracer]

Have you checked the reeds , they will defiantly cause a bub bub bub when the ski is in the water.

I chased a XL1200 all over the place only to find out it was bad reeds the whole time, thing is the reeds looked fine , hold your hand over the carbs with the flame arrestors off, rev it up, doesn't matter if it is in the water or not , if you get blowback through the carbs the reeds are toast regardless of what they actually look like.

 

[tom21]

Hasnt made it to the water yet as it didnt seem able to rev much off of idle.

Ill check as you suggested, thats stupid easy. And thank you for taking the time to respond. I appreciate it.

 

[tom21]

Well, thats probably not it. Suction only, on a positive note the garage is fumigated and the ac is hard at work doing the rest of the house since the air handler is in the garage. Wifes gonna be mad.

Next? I got parts, i got tools. I got no brains.

Not sure if it helps but with the flame arrestor off, its richer for sure and with one carb covered it almost reved more than it has. Like one peak was a few rpm higher than its been.

So fuel or electrical? Other? Dont be shy, jump in the fire! Whatever insight you guys experience has is gonna be better than me systematically replacing parts. Im thinking 80g spring next then on to stator and while the ebox is out and open if that doesnt work the cdi after.

Lots of work, might not solve this, save me some time and give me a better guess. No ideas are bad ideas. Hell, if Terry feels strongly enough ill rip the manifold off and replace reeds if i have to.

I tried to upload video but it says file is too large. Shorter video? What do i do?

 

[WFO Speedracer]

How about the plastic check valve on the jet cover , if one is damaged it won't run on that cylinder until you can get the rpm high enough to get on the main jet, run into that one before , have you checked the sync on the carbs , have you verified spark with an adjustable spark tester, loose baffle in the waterbox or an internally melted exhaust hose , just throwing stuff out there to see what sticks.

 

[tom21]

The check valves are good, the small ones are also good, not lifted. Carb sync, didn't mess with it. Pulled it. Looked at it mounted but didnt feeler gauge it. If its off its ever so slight. Its not missing on a cylinder, i can check spark tomorrow with the light testing tool. Waterbox was fine when i parked it, wouldnt suspect it after swapping out engine from running before. The motor was swapped thats the change. Its something there. The rest was ok on last run. Not arguing, just pointing out what was. Could stuff go bad? Waterbox? Not sure that's possible, maybe? Hose? Sure ill buy that. But wouldnt it be more likely the unknown motor was the culprit? Ill run it down if you think its a good culprit. It literally runs like its hitting the rev limiter, but the limit is set at 2k instead of 5 or 6k.

I feel like the fuel delivery is slow. Maybe run fuel line right to the carb from the tank incase the fuel selector is gummed? It idles and goes a bit above but won't rev out fully. Partial restriction would do that. I cleaned the tank and put new oem fuel lines but just verified the selector was open.

Ill check spark and the exhaust hose. Those seem like possibilities. I think i have a rn waterbox, but ill have to check. Thanks for round 2 suggestions!

 

[WFO Speedracer]

Next piece I would probably suspect would be the stator.

 

[Myself]

Have you measured voltage at the battery while trying to run it?

 

[superjetkev]

After 9 years of not riding i too finally got a ski together over last couple years and has everything "how its supposed to be". Went to fire it up and sounded like the over heat sensor was kicked in. Wouldnt rev. Checked spark and it was random/ weak. In the end, cdi was bad. Would fire right up and idle but wouldnt rev. Not saying its your issue but worth considering. Good luck

 

[E350]

I will be doing this soon on my 550sx. This is a Taylor Curtis video on the subject which I came across:

 

[WFO Speedracer]

I guess some here don't know this or don't remember but Tom used to repair jet skis professionally , that is why I am only throwing oddball stuff out there, I figured he has already has the basics covered .

 

[DE09]

I removed the diaphram and plunger from the carb top, leaving the "valve" closed in the bottom of the float bowl. And blocked off the vacuum port to the diaphram