GT40 takes longer to start when warm

... still starting a little slower than I think is normal... Finally checked the fuel pressure... Interesting results... 31 psi at first key on. 41 psi at second key on (not running). 35 psi running, but bounces from 31-ish to 39-ish along with a bouncing idle... Pumps, regulator, both??? thanks

I ran some Lucas fuel treatment through. I have a new ign distributor installed too. Things were running great but then I lost WOT, it won't go past say 3800 RPM. Which is odd because with my old distributor it would wail. So I checked timing, TPS, dizzy pickup and everything looked good there.

I ran another fuel pressure test and whoa, as I undid the plastic cap fuel was spurting out. 2 surprises 1. the Schrader valve leak 2 I had fuel rail pressure, after an hour or two sitting.

Problem I have now is fuel pressure drops to 20 PSI at anything over say 58km/h 3700 RPM. It's mid 30's all other times.

Pulled the boat out of water today and new regulator coming from Rock Auto, new injectors going in tomorrow. I'm wonder if I should order the FCC fuel pump.
(I had a 90's Porsche with same sort of mechanical vane Bosch pump and when I replaced it, fuel pressure jumped up quite a bit).  Or the whole FCC upgrade ?

wetskier2000 wrote:   Got a link to the injectors you used? thanks...

C_Heath wrote: FINAL UPDATE!!! FIXED!!!!!!!!! I wanted to for sure let everyone know that my LONG HOT START has been fixed. I want to thank all you guys for the help. You know who you are but especially @KENO.He has spent a ton of time with me and many others to try and resolve their issues. I ran out of time at the end of summer last year but really the only thing I had not changed to Aleve this hot start problem was injectors and the distributor. Well, this spring, I had planned to do one at a time so I would know for sure which one was the issue and the injectors was first up and it fixed the hot start problem. I ran her up the lake with some pretty hard enthusiasm for about 30 min, parked, dropped anchor and waited. After about 20 min I went to fire her up and instead of the 5-8 second wind of the starter I got a quick, crisp start! Under a second. I'm pumped! Thanks again to everyone! Lets hit the water.

C_Heath wrote: FINAL UPDATE!!! FIXED!!!!!!!!! I wanted to for sure let everyone know that my LONG HOT START has been fixed. I want to thank all you guys for the help. You know who you are but especially @KENO.He has spent a ton of time with me and many others to try and resolve their issues. I ran out of time at the end of summer last year but really the only thing I had not changed to Aleve this hot start problem was injectors and the distributor. Well, this spring, I had planned to do one at a time so I would know for sure which one was the issue and the injectors was first up and it fixed the hot start problem. I ran her up the lake with some pretty hard enthusiasm for about 30 min, parked, dropped anchor and waited. After about 20 min I went to fire her up and instead of the 5-8 second wind of the starter I got a quick, crisp start! Under a second. I'm pumped! Thanks again to everyone! Lets hit the water.

So you had a dripping injector , nothing worse than when your injector drips 

Hey Partswapper, glad to hear it's fixed.

KENO wrote: C_Heath wrote: YO!!! Im back! Sorry! Im a true fan not just here for help. I have NOT replaced the injectors or the distributor. I just ran out of time and we actually are having a real fall here in NC. Usually it goes from 90 to 28 overnight. I am planning on doing the last two items in the spring. My boat ran great with the help of some awesome folks here this year. Im looking forward to getting the injectors and distributor as Im sure that this will put an end to my long starts. Thanks again all you guys! You should never ever say you're sure until after the problem is fixed  Good to see ya around and hear the boat runs great except for that nagging little issue

KENO wrote: Chris hasn't been logged on since August 20th. Maybe your question will bring him back with more of his "parts replacement adventure" I hope so

Chris hasn't been logged on since August 20th.

Lol not yet anyhow. I changed to 100% ethanol free now also. It seems to smell better if that’s possible. Less gassy. Hell, that’s just probably me wishful thinking lol.

Update lol.
Just got home from the lake


I think it’s as good as it’s gonna yet. Takes 4 seconds to start now. It runs better, has good power and I’m happy with it. I’m still going to do the already purchased distributor and injectors. It can’t hurt and they are in the shop here so I’m going to get those in soon. We set for a long time today and it was hot. It was after we had ran a while also. It fired in 4 seconds. Not immediately like when I’m getting ready to back it off the trailer but it is what it is. I’ll keep posting updates. Thanks guys

slmskrs wrote: Cool. I actually tried to get by with cheaper 3rd party valve which didn't work right. I got the correct one from SKIDIM and it's ran great ever since. Just keep in mind that you'll always have a little bit of a problem with fuel vaporization when ambient is hot (high 80s/90s). It really cooks under the engine compartment; it's just the nature of the beast with a MFI GT40 in a Nautique. But I hope this helps your engine run better. After checking fuel rail pressure, this would be then next thing I would have tested (since I've dealt with it before).

I have a fuel pressure guage permantly mounted on the rail. Its good 38 engine off key on, 31 idling and holds good pressure for a while.

slmskrs wrote: Hey, just saw this thread. Didn't realize it would be after midnight before I got through most of it. Just curious (in case I missed it)? Did you look into the idle control valve? The issue I've had with both of my GT40s was longer starts when hot, and loping. Never an issue if stopping and starting it within 5-10 minutes. But if it is hot (so extra hot under the engine cover, it is a problem (some level of fuel vaporizing when hot (ambient). I changed y idle control valve and it pretty much resolved the problem (especially the loping). One thing you can actually do to test it when you are having the long start issue (hot). Remove the valve from the throttle body (easy), and then start it. With the valve off, the engine gets more air, so will probably run around 1,500rpm or so.at 'idle'. But if it starts right up with the valve off, you could be having an issue with the idle valve. Anyway, since you've replaced juswt about everything else, something to consider before you spend $$ on new injectors (which I've been thinking about)..

Got it installed tonight. Test run is Saturday. Will report back!

Hey, just saw this thread. Didn't realize it would be after midnight before I got through most of it. Just curious (in case I missed it)? Did you look into the idle control valve? The issue I've had with both of my GT40s was longer starts when hot, and loping. Never an issue if stopping and starting it within 5-10 minutes. But if it is hot (so extra hot under the engine cover, it is a problem (some level of fuel vaporizing when hot (ambient). I changed y idle control valve and it pretty much resolved the problem (especially the loping).

One thing you can actually do to test it when you are having the long start issue (hot). Remove the valve from the throttle body (easy), and then start it. With the valve off, the engine gets more air, so will probably run around 1,500rpm or so.at 'idle'. But if it starts right up with the valve off, you could be having an issue with the idle valve.

Anyway, since you've replaced juswt about everything else, something to consider before you spend $$ on new injectors (which I've been thinking about)..