Bad Check Valve SBN44?

[kawa js550]

Ok Storytime again. I upped my pilot and main jet. Here is where I am at.

140 main
125 pilot (all i had on hand)
2.3 N/S with 95g spring (im around 20-22 psi on popoff)

Check valves look to be good, replaced some loose fitting fuel lines and ran a line straight from tank to carb. Pickup is clean.
Got the ski dialed back in and now both the low and high speed adjuster screws are around 1 turn out. Much happier.

Still having the same issue.... I did some testing and this is what I found. When the ski is cold & not being ran hard, it will start back up right away. If im riding it hard and getting the motor hot, it wont want to start again unless I give it a shot of primer.

Is vapor lock a thing on jet skis? The only other thing I could think of is the reeds that I put back in were not the best but I have run far worse and haven't had an issue like this before. Maybe when the ski is getting hot the reeds are expanding & not sealing on start up?

Good news is I got it topped out at 34mph with a full tank and passenger. From what I found that is around what it should be.

 

[smoofers]

Vapor lock could be an issue given how long the stock fuel line runs are, but I doubt it. Is your fuel tank check valve working properly? When the ski is hot, does the gas cap hiss if you loosen it? Is the gasket on your gas cap properly sealing?

 

[kawa js550]

Vapor lock could be an issue given how long the stock fuel line runs are, but I doubt it. Is your fuel tank check valve working properly? When the ski is hot, does the gas cap hiss if you loosen it? Is the gasket on your gas cap properly sealing?

Fuel tank check valve is good. I didn't think of the gas cap seal. I will have to check that.

 

[kawa js550]

Just replaced my reeds with Boyesen power reeds, cleaned all my gasket surfaces and put new ones on with a thin layer of 1211, checked my fuel pickups, replaced a broken gas cap, and went through the whole carb.

Reeds were useable but worn out. New ones seal to cages tight.

Gas cap was cracked in the threaded area so replaced that. I blew through the return line and no more hissing from gas cap when tight.

I came across this write up on how to make sure your check valves are properly working. After testing I found that my check valves were not sealing off. I replaced them and now they are sealing. I ended up using a dull ball endmill to push the rubber grommets through. It worked very well. I struggled the first time and must of creased the check valve.
https://www.seadoosource.com/mikunitests.html

I highly recommend taking a look at this link. Explains how to fully check your SBN.

Everything is back together. Will test on the next warm day.

 

[kawa js550]

Took the chicken out for its maiden voyage. Way more responsive than before with the new reeds and starts back up every time no issues. Think this pesky check valve was the starting issue. Thanks everyone for their input.