Warm starting issue on 2001 SAN GT40

Well took her out for the first time yesterday. She started up right away and pulled hard. We did run into a issue along the way.

Had something weird happen, after cruising around for a bit, we found a calm spot and decided to stop and drop a rider in. After rider was ready tried to restart and it would just keep stalling out. Only way to get it running was kind of a neutral drop. Put in neutral, start and give it some gas, and quickly shift back and engage gear. Prop would spin and you could just put back in neutral and it would idle fine and run great all day. So it was just in the initial kick over only. When the boat sat and cooled down it would start right up, and only experienced this when engine had been running for a bit and shut off briefly.

Sounds like it might be vapor locking.

how do u fix that?

I am not too sure on that motor. I know on a Mercruiser there is a cool fuel system. That lake water runs through to keep the fuel cool and it doesnt vaporize. I am sure there is something on the pcm similar.

If its a vapor lock that wouldn't fix it so I'm going to say sounds like a fuel pump issue. Once you vapor lock it stays locked until you get the air out.

Why would it be a fuel pump if the issue only happens when the motor is warm? Cold starts are fine.

some guy on planetnautique had same problem

i forgot the fix he did

Does it smell and/or smoke when it finally does start?

nope

I had a problem that sounded just like this.

A way you can find out what it is.

When your boat is in the RUN MODE. That's what your boat is just before you turn the key/or hit the start button to crank the motor. Ya know the PP is lit the start up beep has gone. You should hear the fuel pump cycle. If you turn the boat to the off and then on position again you will hear the fuel pump cycle everytime. If when your boat is having this problem you don't hear the fuel pump cycle then "YES" you have the same problem as me.
Its a bad connection going to the fuel pump relay's at the back or front of the motor. Many peopel will tell you to replace the relay's. Its a quick easy cheep fix and some times it works. There is a Fuse-able link wire that can and will go bad. It's a Purple wire comming from the relay pack. To find it start playing with the wire loom at the back of the motor. Moving this wire will cause the fuel pump to cycle on and off if its a bad connection. It only did it when my boat was warm. It would get hot and then cause the connection to expand and stop the boat every once in a wile as soon as it cooled down for a second it would start right back up and may or may not do it again for like 2 weeks. It had me chasing my tail for 2 years. Simply cut out or replace the bad section of wire and your good

Grant, if that was the case why would a neutral drop work? and after the following everything behaves normally and idles fine?

(Message edited by liquiddiet on April 29, 2009)

No a neutral drop . i never tryed that. My problem was like the safty switch was disconnected. It would run for just a second and then Die.
There is a Start relay and a Run relay when the boat would switch from one to the other that's when the boat would die

Grant-

Is the relay going to be on the bow side of the motor on a v-drive?

We see 2 relays right near the ECU and a purple wire but wiggling it would not cause the pump to prime or anything. Was it a solid purple wire or was there a tracer as well?

Swapped in 2 new fuel pump relays and a 4 hour session with about 20+ warm starts with no issues!

$16 fix.