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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3721
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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My jet ski randomly cut out on me once... It was running

Customer Question

Hi there! My jet ski randomly cut out on me once... It was running just fine for about an hour and then wham.... Just shut off as if it ran out of fuel or something, except the tank was half full... So we get it out of the water, rebuild the carb, try pouring fuel down the carb and into the two plugs... Not much. It cranks like crazy but when it turns over, it turns over for about 3 seconds and then nothing, or its half cranking and you can hear it starting to give that deep bellow like its about to turn (which even if it did, it would only last 3 seconds)... But I figured out when I leave the plugs on but pull the tops to them, so it's just plugs into the top of the engine, without any electricity flowing to them, and I run the starter for about 15 seconds... I can then put the caps back on the plugs and run the starter again, and it fires right up for about 5-6 seconds and then kills again. This is a 1997 seadoo gts bombardier. Not sure what the problem could be... Carb is getting tons of fuel, it isn't fuel pump. I just rebuilt the thing but never did a pop off test for the needle and seat. But I don't think that's the problem. Thank you so much for any help you can provide, I really appreciate it!
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you.

You wrote that you just rebuilt the thing. Was that the engine or just the carbs and fuel pump?

Customer: replied 1 year ago.
Hi there charles! I just rebuilt the carb, and the fuel pump is obviously in the carbs and it was working great. I took off the fuel out hose and it pumped fuel out of it like crazy, so its definitely getting fuel into the carbs
Customer: replied 1 year ago.
my cell is(###) ###-####if you want to call. Im totally fine with this or over the phone i don't mind
Expert:  Charles replied 1 year ago.

With the cranking that you can do, and them install the plug wires, this is telling me that you are nor getting enough fuel into the cylinders to fire the engine off. you are gong to need to set the pop off on the needle, and ensue that all of the jets have been removed, cleaned, and then reinstalled.

Customer: replied 1 year ago.
Okay well what can i run through the carb that will safely clean it out... i obviously clean all that i can see but all the different routes and all look plenty clean! I'll do pop off though, I think its supposed to be 28 psi... its a mikuni bn40i carb... you think the pop off is around 28psi?
Expert:  Charles replied 1 year ago.