Sport Jet 120 has spark, fuel, and cranks... no start

[jaysonbee]

Ok... I was in the Bay in NC, and for the first 3 days I ran the boat, it ran fine. Last day it was taken out, was WOT then the power dropped to an idle speed, and any backing off the throttle would result in the engine shutting off. Boat would not restart when I took to lake on way back to clean out the saltwater.

What I've done:

1. Checked for spark (used timing light and got what I would consider a normal light pulse)

2. I cranked and cranked, and logic would dictate that eventually some fuel would dump out the exhaust... but nothing.

3. Took apart the fuel pump, checked diaphragm, screen, gasket. all OK

4. Left outlet hose off the pump and cranked, fuel dumped out of the outlet port.

5. Pulled the bowls and checked for fuel, bowls were full

6. pulled Black / Yellow wire from rev limiter to see if REV limiter was faulty. No difference.

I've had had this engine apart when I bought the thing and have rebuilt everything but the powerhead itself. (only 40 hours on it)

I hooked everything back up and tried again to crank, got nothing... also, just to check if it needed to be primed, squirted a little starter fluid in carbs, but it would not fire. Any help on this matter would be greatly appreciated.

Thanks,
Jason

 

[kend301]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

Carb vents need to be clear for the fuel system not to vapor lock , check them , Where in NC are you ?

 

[jaysonbee]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

Hey Anomaly,
Thanks for the response. I'm in Durham NC. That would have been the first thing that I would have checked, had I not just completely rebuilt both carbs. When I say rebuilt, I mean I drilled the welch plugs, soaked them for a few days, and then installed. This was the original problem with this boat when I bought it. However when I bought it I had the complete opposite problem. the plugged float bowl vents were causing fuel to dump into my #4 cyl

Its a Regal rush XP and I picked it up for 2000. and its in near perfect condition... I will pull the carbs again and check for residue and get another kit, but if this is going to happen every 30 - 45 days... its not worth it for me...
Are you pretty sure this is the issue? It definitely makes sense, however just puzzling how about 2months ago I could completely rebuild them, then have the same issue happen again.

Anyway, thanks much for your response. I will pull them tomorrow and see if there are any obstructions

Regards,
Jason

 

[Oode]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

When Jason and I get our boats running correctly (may be spring for me :-( ) we should have a "jet-in" somewhere...

If yours is a 96, and if we need to do some part swap trouble shooting, I'm in Raleigh.... and happen to have my marginally functional top carb off at the moment as well...though I think I located at lest one issue, a missing gasket on the inside of the float bowl....

 

[jaysonbee]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

Hey Oode,
No doubt. I've become quite the expert on these things... Hit me up at khemik@gmail.com... can def share knowledge... seems mine keeps gumming up the carbs... havent had them rebuilt for 2 months and it appears to be another apparent blockage. I'm taking them off tonight... I'll post my findings. Thanks

Jason

 

[jaysonbee]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

Anomaly,
One question I do have is: Assuming that the vents are blocked, what reason would you have for the boat not starting with starting fluid? Seems to me that the starter fluid should have at least got it to rev for a moment. Just curious. I'm going to check the carbs tonight (hopefully) and I'll let you know what I find.

Thanks again,
Jason

 

[kend301]

Re: Sport Jet 120 has spark, fuel, and cranks... no start

AHHH .. Starting fluid
1 the boat was not built to need it to start ... meaning you have a problem
2 starting fluid is all either based and most people will spray until the engine starts , this will wash all oil off the cylinder walls and blow stuff up !