Help! 2001 Supra Launch problem

[DeanoFF]

I have a 01' Supra Launch and having troubles with the engine firing, starting, then cutting off after several seconds. In every instance i have taken the boat out for several hours with it running perfectly wakeboarding and turning it on and off it was fine until several hours later towards the end of the day it does this thing where it starts then cuts off after several seconds. It startred about 3 weeks ago and after the first time of being towed in i decided to change the fuel filter out thinking it was clogged and it would be quick and easy. I took it out for about an hour by myself and it ran perfectly. So the next weekend I took it out once again ran it all day turning it on and off throughout the day and it ran fine until several hours of being out there i went to start her up and she started up but cut off once again after several hours. So i took it to the shop they changed out my spark plugs and distributor cap thinking that might be the cause. I took it out and after 15 min of me taking it out same thing happened again. A tech came out to the water and hit the fuel purge valve nothing came out where fuel should squirt out. So I put in a new fuel pump thinking that had to be it took it out memorial day weekend and wakeboarded all morning from 8-11 turning it on and off several times and it ran perfectly. Went to lunch at the marina came back out and the same thing happened it starts then cuts off after several seconds. It seems like it might be electrical possibly a sensor that gets hot or something causing the fuel pump to stop working after several hours. The only thing I can think is to get the comp on it when the problem arises because I believe if it wont show up when its running good. If anyone has any input I would appreciate it.
Thanks

[pepowdylan]

Hey, I'm very close to you in Knoxville. Have you had any prior issues? What lake are you on?

[DeanoFF]

No problems before no and I live downtown Nashville so I go on the Cumberland River downtown....Old hickory lake and percey priest.....and I usually make it up to Center Hill and Dale Hollow one or twice a summer....any thoughts on whats going on with mine?

[pepowdylan]

Norris is a great lake around here! Cleanest around that I know off. You can see about 20ft to 30ft under sometimes. It definitely sounds like it could be a overheating issue. You could be going the right direction with the sensor. It would be shutting off if it was overheating. Make sure the impeller is not clogged in any way and that water is pumping correctly to the engine so it will cool off.

[DeanoFF]

Thanks man...I actually have been on Norris several times when I was in college great lake just too far for me to drive up to

[FlatH20]

impeller would be a great thing to replace - it sounds like the classic vapor lock... my last boat, a moomba had a similar issue - next time it happens - grab a towel get it wet and wrap it around the fuel pump and/lines - if it stops after you cool them down then that is what your problem is - the fuel is getting too hot and vaporizing.

also try keeping the blower going this should keep the engine compartment a bit cooler. what is your temp gauge reading when the problem occurs?

[ridininmd]

EFI or carbed motor?

[opie]

What octane gas are you using? I filled my 05ssv with 87 once (not thinking), and it vapor locked like craze until i ran it all out. Sux to fill it with premium but I'll pay the extra to keep from having problems. My $.02

[DeanoFF]

So I talked to a guy at Indmar and he told me to replace the anti-cyphon valve because this could be causing more air to get in the fuel. Other than that I had a couple mechanics tell me that putting in the premium fuel and some stabilizer could help the fuel stay cooler. Also, he said if that doesnt work to put a wet towel on the fuel lines and pour water on to the fuel pump after sitting for a little while. He said I could also run my blower while I sit and keep the dog house open if I sit for an extended period of time. Noone really had an answer to why it is doing it now. I did have one mechanic say you could replace your fuel lines and said they could possibly be clogged up from the ethanol in the fuel now. I also heard putting the wooden clothes pins all over the fuel lines and this will help absorb heat and possibly help stop the vapor lock. I took it out the other day ran it all day wakeboarding here and there sitting for 30 min at a time before turning the engine on and it ran amazing. Around 3 I turned it off and I sat for around an 1-1.5 hours before turning it back on. It turned on and ran shitty for about a minute before dying. I tried turning it on again and it turned over and ran for a couple secs before dying again. I opened my doghouse turned my blower on and poured some water on the fuel lines and fuel pump and waiting a sec then it started up fine and ran amazing the rest of the day. It just baffles me it all of a sudden is doing it and there doesnt seem to be a mechanical fix except for possibly replacing my fuel lines. Thanks for yalls help

[zero2460]

Hey, I had the same problem with my '08 supra launch. There's an issue with the fuel lines where they run too close to the engine block right under the rear seats. When you run the boat hard, then shut it off, the residual heat from the engine boils the fuel in the line and causes vapor lock, stopping the flow of fuel to the engine. This is why it only shows up after your run the boat for a bit, and also why the boat will run for a minute or two then shut off after the problem does show up.

Basically, you need to wait for the fuel in the lines to cool to the point where the vapor turns back into liquid. Putting anything on the lines that will act as a heat sink will do this- such as the wet towel or pouring cold water onto it. Keeping the line from getting too hot in the first place also works- this is why opening the doghouse or running the blower helps. IF you're looking for a quick fix, just disconnect the line just before the fuel filter and siphon fuel through it until it starts running out- this will draw out the vapor and break the lock. Solves the problem every time.

As far as long term fixes, you have two choices. One is to put some insulation between the fuel line and the engine to protect it from the heat of the engine, so it doesn't overheat when the boat is stopped. This worked only part of the time for me- after running the engine for a while in hot weather, I still got vapor locked.

The second option is to install a second fuel pump that can break the vapor lock once it forms. The new '13 Supras (and maybe '12 too) have this. After spending some time on the phone with Supra, we were able to get them to apply this fix to our boat as well, free of charge- awesome! Since the second fuel pump was installed, we haven't had any problems. Hope this helps!

[FunkyBunch]

^^^^^ this is your answer have seen this issue on the Supra's for years. I think the fix came out in 09 though.