1996 SPI starts and runs great, then bogs down after 30 mins of riding.........

[JKSTI&R1]

Hey Guys,

Ok so ill make this quick. I did the full maintenance on the ski, clear lines, pump oil changed, plugs, cleaned and rebuilt carbs and set to factory specs, pet cock done & Compression is 150+ in each cylinder. We took at the ski last Sunday and it ran great for a few hours then started bogging down. It will start right back up every time and say idling, but give it gas and it dies. I took it out today, changed the plugs again and it ran for about 30 mins. Was still in bog mode you can say, I feathered the throttle out on the lake for a few mins and it cleared up and ran for the 30 mins and then it did the same thing again. Do you think its the N&S needs replaced?

Thanks for the help guys !!!

 

[mikidymac]

First thing is stop running it. The bogging is it running lean and will quickly destroy the engine and more running never clears it out.

I would pull the carbs and check them to verify clogging and correct pop off and leak down.

Did you replace the needle and seats the first time?
Did you replace the fuel strainer and selector?

 

[JKSTI&R1]

I have never replaced the needle and seat, single carb...... Not sure if this makes a difference but it will run fine off the trailer, thats why I even went back out to the lake after I changed the plugs. So if its lean, how would a rich running ski act? Serious question

Will be pulling the carb tonight and open it up and see whats going on. I did clean the filter in the carb and also the fuel/water sep screen. Pet cock is new.......

So does it sound like maybe the main fuel jet or area is clogged with something? Everything was new I used, so not sure how it could get clogged in just a few hours..... ???

 

[mikidymac]

Usually if the needle and seat is leaking it will be flooded and hard to start.

 

[JKSTI&R1]

Ok, gotcha..... It stars right every time. Even after a week of sitting, so it might not be that.........

 

[mikidymac]

That sounds correct.
Have you checked the fuel system for air leaks.
Also when you rebuilt the carb did you replace the spring?
Did you use a genuine Mikuni carb kit?

 

[JKSTI&R1]

I have not checked for air leaks yet. I did NOT replace the spring in the carb and yes, it was real Mikuni kit.......

 

[mikidymac]

All good news.

 

[Bills86e]

Heres a few. Replace the 3/32" id iol lines while down there and prime the oil pump. Grease the two zerks, pto & drive. Might be time to change fuel lines and pulse, as these may have cracks and loose connectors. Check exhaust couplers, any engine compartment leaks will cause your issue. If you get water in bilge when shes been crapping out, the tuned pipe welsh welds may have a spraying on the electronics. Checking the *plugs usually can help determine combustion health. ALWAYS fog engine at shut down. Water in tank will settle to bottom where it can enter the fuel baffel, so either drain it or add a cup of isoprople alcohol to delute it enough to go through the system and be used up.

Bills86e

 

[Mickirig1]

Did you check pop off when you did carb? Have a pressure tester? The repair manual, available on the Internet for free. Has the pressure test procedure of fuel system. Try pulling choke when it bogs? If it goes better, you are running lean. DO NOT keep trying to get it to run better while lean! Look at your water separator / fuel filter under the front hatch. The flat gasket tends to split or not seal. It sucks air, which is easier to suck then fuel. Did you add a fuel filter before the carb. It will catch junk in the line or tank.

 

[mikidymac]

50/50. Some like to add another filter before the carb I am not one of them.
If you clean your fuel tank and overhaul the fuel system the factory strainer is more than adequate. I feel the additional filter can add restriction.