gt-40 not always starting

Sounds like your battery has some bad connections. Check the terminals and make sure they are clean as a whistle and tight. Give the battery a charge and if in doubt, bring it to an autoparts store or marina and have them do a load test on it make sure it is holding. You could also have a stuck solinoid at the starter... cheap part.. but if it happens to not start again when you turn the key (no starter engaging) take a hammer and tap the solnoid to see if the plunger is stuck. If it turns over then, you can probably tell it's the solinoid

Sometimes if the timing is too far advanced, the car is difficult to start, particularly when it's hot. Check the timing.

Also check for moisture buildup in the distributor. It would show as condensation in the cap and would only be there after running and would evaporate after sitting a while.

Oh... it turns over... then its probably not the battery or solenoid. Check the safety lanyard. It's pretty stupid to do this, but the next time you are trying to turn it over and it will not fire, pull the lanyard out and push it back in. I had an OMC outboard do this to me about a month ago. I went all around that engine, even replaced the power pack and it turns out it was just a bad connection at the safety lanyard. Fired up first try.

If the boat has had any moisture build up, the connection to the lanyard could be bad causing it think it's been pulled. They are fairly cheap to replace if you narrow it down to this.

My brother Todicus and I have both been fighting demons in our boats.

I have learned here and other places that many of the GT-40 problems are electrical in nature. They won't tell you this at the dealership. Most of the electrical problems are connection related: bad grounds, corroded connections, etc.

My problem was a fuel pump relay connection. If when you click the ignition, before the starter engages, you should here 2-3 seconds of clicking. If you don't hear that, then your fuel pumps are not pressurizing. Tis could be a bad relay or connection.

To check the fuel side completely, check all of your filters and screens along the fuel system. I dont' know your model but there was a screen in the tank, at the angle stop coming out of the tank, and at the low pressure fuel pump. Change your fuel cell filter. I read that a fella had a similar problem and replaced his low pressure pump, anmd his problem was fixed (115.00 at skidim.com)

Check your connections to the fuel pumps.

Check your main wire that comes off the ignition coil.

Check all electrical connections. Open them up and inspect. Put a bit of dialectric grease on the connections and reconnect them.

Check your grounds.

If you can get it to start, work your way around the motor and wiggle all electrical connections. You may find something.

Check the electrical connections to the pump. Check the relay. Replace the relay just for kicks. They are cheap and easy to do.

A nautique mechanic told me they have a lot of problems with the low pressure pump. Replace that first. SKIDIM.com has both pumps. 115.00 for the LP and 125.00 for the HP if I remember correctly.

Hard to imagine both of them going out at the same time.

That is the right one......... you should by two and replace both relays, just to make sure. You have the identical symptoms that I was having on my '95 gt-40. See if you are getting power to your relay with a test light with the ignition on. I would get the clicking, but the pumps would not energize and I had no power to the pumps. I worked backwards from the pump, then relay and found that I was not getting power to one of the relays. Found the problem in the battery compartment.

I replaced the relays I bought reom SkiDim anyway, just so I would have peace of mind.

Glad to hear you got it working........... the GT-40 EFI's are a little tricky to diagnose. But once you get it running well, what a great motor !!

Have fun at the lake !!

that seems to be one of the most common problems for that motor might be wise to have a couple relay's on hand for future use if it pops up again.