Poor Man's GT40 Diagnosis

I downloaded your spreadsheet on the GT-40.
I have a 1994 Hydrodyne grand sport, it has the GT-40 pro boss, great engine.
These Nautique forum's are the best place I can find about the GT-40 and the Hot start problem.
I've had the boat about 20 years, maybe the last 7 it's had the hot start problem.
I've tried a few things on the spreadsheet before and will try to go through the rest and hopefully get it fixed.
Thanks
BB

I bought a 98' Ski Nautique this year that had not been used much in recent years. The seller had it de-winterized before putting it up for sale and said it ran great (of course). I got it and the second time I had it out it died on me after it had been run for a while and warmed up. Then I started it back up and it immediately died. Started it again, it did its initial up-rev and died again. Then on the 3rd or 4th time it started and kept running like normal.
I thought maybe it was bad fuel from sitting for quite some time and not being used much, so I topped it off with new fuel and added sea foam for the next trip out. It went without incident.
A couple weeks later we were headed out again and backed down the ramp to launch and the boat would start, do its rev-up and then immediately die. Repeat about 6 times.
It finally started and ran like normal so we headed across the lake to our spot (about a 5-10 minute drive). About 100 yards away from the beach it cuts out and dies. Then I re-start it, it starts, revs up and immediately dies. Repeat 6 or 8 times. Then it starts and runs like a champ until the end of the day, when the cycle repeats again.
The problem is sporadic and impossible to duplicate. So far I've replaced both fuel relays and the fuel filter but couldn't get out before the weather turned to see if that fixed it. Both fuel pumps seem to be running fine as you can hear them fine when you turn the key. I'm pretty confident it's not the kill switch.
Another notable trait is that it seems to rev higher and longer than it should upon initial start-up, and takes a while to come back down to normal running rpm. I'm not sure if that's related or not. I know the GT-40's, and most others, do rev a bit on start up, but it seems higher and longer than normal.
Other options I'm checking into further are the anti siphon valve and the idle air control
Update:
I went to get my boat ready for summer today after it was winterized. I replaced the emergency kill switch today just in case it was an issue too. Put new belts on and went to start it up and... it started and revved up for a second and turned itself back off. After repeating that several times it would not stay running. It starts, revs for a second and shuts itself off. I replaced the battery terminals and put a new connection on the wire coming off the positive terminal, as I’’d heard that was a common problem (called the stay run wire or something like that). Still no luck, it continues to start and then shut itself off. I checked the fuel pressure, it’s at 40 when it pressures up and goes to 45 when it fires and then goes back to 40.
Seems like maybe the computer is shutting it off. It doesn’t have a crank position sensor.
Any other suggestions?

No start (OK, it'd start 1 out of 50 tries) caused by bad cell in the battery.
Even when jumped off another battery, the bad primary battery (only have a cranking battery in my boat) was wreaking havoc on the fuel delivery in some way.

Thought for sure, it was fuel pump/relay related...

Nonetheless, worth sharing...

Bri892001 wrote: No start condition solved by cleaning/repairing engine 10 way harness as described here: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=42231&PN=1&title=diagnosing-no-start-gt40 I added in the No Start column and created a new row Corroded 10 Way Engine Electrical Harness Updated Spreadsheet

That 10 way connector is really an 8 way connector and it seems like putting something in the spreadsheet about the manual being wrong in reference to the connector would be a good idea too.

I never got around to logging this one. Intermittent loss of power at speed fixed by replacing distributor. The base problem was a loose/dislodged PIP Hall Effect Sensor.
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=41558&PID=538985#538985

I logged it under the
Distributor Complete Rebuilt Row
and split between the Hesitation and Reduced Top Speed Columns

Updated Spreadsheet

No power in gear fixed by replacing faulty fuel injectors as described here:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=41742&PID=537812#537812

Logged in the Hesitation column in the Fuel Injectors row on the spreadsheet
https://docs.google.com/spreadsheets/d/17VemuIOaa9i8kEply-ZmFOSyjyzz8rd7B0WEuIT_6S0/edit?usp=sharing

On the skip on acceleration the plugs were Platinum and looked brand new, I really think the module fixed the problem. Just my opinion.

Lack of power after overheat fixed by replacing fouled/damaged spark plugs as discussed here:

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=41631&title=need-some-gt40-help-gents


Logged on spreadsheet in broken spark plug row and split in the columns for Hesitation and Reduced Top Speed:

https://docs.google.com/spreadsheets/d/17VemuIOaa9i8kEply-ZmFOSyjyzz8rd7B0WEuIT_6S0/edit?usp=sharing

Low RPM misfire fixed by replacing broken/damaged spark plug as described here:

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=40837&PID=526898#526898

Added broken spark plug rows to spreadsheet. Same spreadsheet link.

Fuel Pump (FCC) not priming because of loose battery connections.

As described here:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=41292&title=fcc-issue-where-to-start

I added a new row in the spreadsheet for:
Tightened Loose
Battery Connections

The MAP sensor on the GT40 is shown in picture below just above the ACT with the vacuum line running to it. Look through all the google images that the search found, you will find one that looks the same.

Unclogging clogged fuel pickup screen, solves runs&dies fuel starve problem as discussed here: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=40597&title=98-gt40-rpms-drop-when-engine-warms-up

Updated Spreadsheet added in Clogged Fuel Pickup Row, Runs and Dies Fuel Starve Column: https://docs.google.com/spreadsheets/d/17VemuIOaa9i8kEply-ZmFOSyjyzz8rd7B0WEuIT_6S0/edit?usp=sharing

Anyone have a motorcraft part number for the MAP sensor, i did not see it int he spreadsheet, surely somebody has replaced it

Baffle Broken Loose, restricting muffler and causing reduced performance and slow acceleration.

Fix was to repair muffler.

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=38572&title=gt-40-slow-acceleration

I updated the spreadsheet and added a new row for the broken muffler. I logged it under the reduced top speed column:
https://docs.google.com/spreadsheets/d/17VemuIOaa9i8kEply-ZmFOSyjyzz8rd7B0WEuIT_6S0/edit?usp=sharing

Fuel pumps not running = engine not running. Fixed by replacing ECM (ECA is the correct terminology as explained by Paul, AKA the engine computer) Relay. This is one of the two relays in the back of the motor. One of which is for the fuel pumps and one of which is for the ECA:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=39443&title=gt40-fuelpumps-not-running

Updated Spreadsheet:
https://docs.google.com/spreadsheets/d/17VemuIOaa9i8kEply-ZmFOSyjyzz8rd7B0WEuIT_6S0/edit?usp=sharing