Superjet dies/seizure at the end of each run

[Killerpirate]

ThanksVumad, i just taken apart the pump and all the gaskets stayd in 1 piece. Also the filter looks very clean!

BTW, what do you think about hydrolock? Water in the intake or fuel? I drained the fuel tank but cant get the last drips out of there.
There is almost no water buildup in the ski, so water in the intake doesnt sound realistic to me.

 

[Vumad]

ThanksVumad, i just taken apart the pump and all the gaskets stayd in 1 piece. Also the filter looks very clean!

BTW, what do you think about hydrolock? Water in the intake or fuel? I drained the fuel tank but cant get the last drips out of there.
There is almost no water buildup in the ski, so water in the intake doesnt sound realistic to me.

Hydrolock is caused by fluid in the cylinders preventing the motor from moving. It's bad news because the starter is strong enough to blow out the crank bearings. Water can come in through the intake or it can actually hydrolock from too much fuel, but fuel hydrolock is only going to happen during storage with leaky carb needles and the fuel left on.

Water in the fuel wont cause hydrolock. Hydrolock requires a volume greater than the dome preventing the motor from turning over. That's not your problem.

Contamination in the fuel could be a problem, but it's not likely your problem. Water in the fuel in small amounts will make the ski run poorly, but it usually will still run. Either the water is in the carb or it isn't. It could prevent running but the water would still be there after sitting for a while so that wouldn't match up to your complaint of letting the ski rest and then it works.

Water ingestion through the intake could match up with what you describe, but it is unlikely, as sitting a while often doesn't fix that problem either. Water ingestion is also very rare with normal riding using the stock airbox. You really have to abuse a ski to get water ingestion using a stock airbox.

 

[E350]

Good for you! Learning about your ski! I would put the carb back together now without more disassembly and run it and when the problem arises, immediately check for spark.

 

[Big Kahuna]

Vumad you may be on to something. Water in the cylinder from a leaking head gasket/oring from waterjacket. May not leak when engine is cooler. as it heats up could possible start spraying water into the cylinder causing the charge to get cooled enough to choke out or kill spark all together. Have you pulled the head. ?

 

[Killerpirate]

Thanks for the replies! Really appreciate it.
I drained the fuel tank, just in case couldnt find any water, so thats good.
I put the carb back in place.

I think my next step is to swap out the CDI and checking the fuel lines. Hoping that would solve it.
What do you guys think about the piston colours ? (See photos)

 

[Vumad]

Thanks for the replies! Really appreciate it.
I drained the fuel tank, just in case couldnt find any water, so thats good.
I put the carb back in place.

I think my next step is to swap out the CDI and checking the fuel lines. Hoping that would solve it.
What do you guys think about the piston colours ? (See photos)

I wont comment on piston colors. It's not something I am experienced in. Those plugs look like something I would be happy with.

Vumad you may be on to something. Water in the cylinder from a leaking head gasket/oring from waterjacket. May not leak when engine is cooler. as it heats up could possible start spraying water into the cylinder causing the charge to get cooled enough to choke out or kill spark all together. Have you pulled the head. ?

Wouldn't that steam clean the plugs? I also felt he was describing that the problem resolved after resting. I would think that if water was in the cylinder, it would still be there in a hour, making for hard starting. Worth consideration though.

Thanks for the replies! Really appreciate it.
I drained the fuel tank, just in case couldnt find any water, so thats good.
I put the carb back in place.

I think my next step is to swap out the CDI and checking the fuel lines. Hoping that would solve it.
What do you guys think about the piston colours ? (See photos)

Test one thing at a time and make sure it is in spec. Being stock keeps it easy. You are working on the fuel so just make sure that is right before you move on. Fuel tank is clean. Pet cock doesn't leak (can use popoff tester for this too). Inline fuel filter is good. Carbs are all clean and test properly. Tank vent works. Fuel quality is good. Since you have the carbs off, be mindful of the carb base gasket condition.

Make sure all of that is good before you move on to electrical. Yes, I have said I suspect electrical but you are dealing with a gremlin and the best way to get rid of gremlins is to pick a system (fuel, electrical, engine, etc). You have started with the fuel system so finish the fuel system.

 

[Vumad]

I recently had a bad battery on my superjet, bought a new battery, had the same problem, thought it was the starter, dissembled the entire ski assuming it had to be a bad ground or a bad starter. Was placing an order for a new battery but had my new $140 battery tested first. Brand new battery was bad.

Similar story with my SBT rebuild kits in my mikuni carbs that still ran poorly and the issue was that they leaked. Also had leaking venturi with brand new needles.

Inspecting and testing are not the same. If you want a great running ski, moving from cleaning and inspecting to properly testing really makes a difference. It takes a lot to learn and you never stop learning, but the attitude you have is ideal for that.

 

[Killerpirate]

I THINK I FOUND IT
Went out today with cleaned carbs and fuel pump and fresh fuel and full tank. Just went to test if i put the carb and pump correctly back together. Jetski worked fine. I thought, lets put it on Reserve. After that, 5 seconds later it holds back, and died. Wouldnt start. Put it back to on and fired right up after a couple tries.
Did the same a couple more times and it kept happening. So i guess is the next step is to check the reserve pickup and fuel knob.
I will keep you updated! Thanks for everything