Rapcap

I have an intermittent problem with my 500 EFI which seems to be happening more and more often. When the motor is cold, it starts perfectly; first crank every time. The problem ocurrs when I have run the motor up to full operating temp (like cruising around the lake for a while) and then shut down for a period of time- like an hour or so, and then go to start. The motor turns over, giving one quick "fire" like it normally would- but then instead of starting, it doesn't "catch" and continues to crank. From that point on, I can crank it until my battery dies and it won't even fire. The only trick I know when this happens is to let it sit for 10 or 15 min, and crank it; most of the time it fires up. Sometimes, lately, it will only give an initial "fire" and not catch- and I have to repeat the 10 -15 min wait process before I get another chance to try starting it. Sounds almost like it's flooded- but it's an EFI motor?? And I don't smell any fuel in the engine compartment when this is happening.

Has anybody had this issue with a 500 EFI or similar motor? If so, anybody know why this happens and how to solve the problem? Thanks!

Rapcap

I forgot to mention; the electronic fuel pump energizes and I hear it pumping like normal for a few seconds-- it does not seem to be part of the problem. Also, if I restart the warm motor right after I shut it down, it always fires right up; it's only after it has sat for 10 min or more that this problem happens.

Thanks!!

xhere

I had one do the same thing as you described...I ended up turning the blower fan on 5-10 minutes before I left and it started every time...If I remember correctly it was always the stb. motor and the fuel pump location was between the two motors and held more heat which I assume would boil the fuel on a heat soak situation causing air bubbles in the system...

thirdchildhood

iTrader: (6)

I think that's why they went to the combo electric and mechanical pumps on the 525.

smcser

Their was a TSB on a problem like this but was for the 502 EFI Mags. Before you shut it down open the engine hatch for a bit and when possible leave it open to allow the heat to escape. I will see if I can find it but I am sure someone else will chime in...........

Rapcap

Thanks you guys-- I will try those suggestions. I would be surprised if it is a heat related problem, because like many of the folks on here, my boat runs borderline too cold- espicially now while the water is still fairly cold. Last summer the boat would do this maybe once every 20 starts- now it seems to be doing it every two or three starts while out on the lake at operating temps..

Irishtornado

Have you ever changed the fuel filter on the fuel rail located at rear of engine by distributor?

I've never experienced what your describing, but I do run my blower 5 minutes before I start it just to avoid a KABOOM.

Rapcap

Irishtornado, no I have not- but would a dirty/clogged filter cause problems only under those conditions?? Seems like that would produce problems while running and during cold starts too? Once the motor starts, it purrs like a kitten and never skips a beat under load.

speedjunky 123

Just for grins, hook a timing light to the coil to cap wire and check for spark. At a mininum it rules out the igniton side.

Jpzaluski

I think you're going in the right directly with the vapor lock diagnosis... BUT ... I had a 500EFI that did almost this exact same thing for one entire season. Mine would eventually start but sometimes I'd give up for 5-10 minutes then try again and it'd start right up. Drove me absolutely INSANE. Ended up being a loose pin in the main connector. For the sake of doing it, pull your connector apart, spread the pins a little, and make sure everything is good and clean. Would have saved me a lot of headaches.