GT40 experts required

I've been experiencing an issue with my GT40 (20 annyversay) in a no CC boat for the last few months.
After a really great running summer, I stored the boat for 2 months on winter, as soon as I started this season it developed a slight miss or hiccup, more noticeable at planning speeds, as a random cylinder didnt fire. sometimes it was really rough and for some running periods it was barely noticeable or did not occur. Some days boat started great and started missing after a 10 minute period run.

My first thought was a fuel issue, so I drained the FCC, changed the filter, cleaned checked the LPF screen.
Checked fuel pressure, 35psi at idle, noticed a quick drop to 0 after shutdown, so I replaced the FPR. pressure now drops slowly to 10psi, but issue still present.
Also gave the injectors a bath in the ultrasonic cleaner, replaced all orings.
Also started using premium grade fuel, and draining the FCC on each outing to eliminate any alcohol/water.
No antisiphon valve is installed.

Also thought after some months of storage in a closed humid enviroment such as the motor box, I thought on moisture affecting the electrical/ignition, so I did thew following:
Checked on cap and rotor, no visible cracks or corrosion on posts.
Switched the FP and ECA relays, made no difference.
Checked spark plugs, all 8 are more carbon coloured than tan, (boat's a bit overpropped)
Sprayed contact cleaner on ignition, ECA and sensor connectors.
Also ran the boat without the tach to discard it messing the ignition.
Ran the boat with both the oil pressure and temperature switches disconnected.

Last time out, boat was really low on power, So I checked compression and all soldiers are in great shape at 150psi, but i'm still clueless on what to try next.

Situation being a scanner is locally unavailable, and parts are really hard to get by, I 'd appreciate to get some advise and guidance on what to check or test next..
thanks in advance.

I am as far from an expert as the moon. I had one acting similarly a few years back. It ended up being a loose wire on one of the fuel injectors. Where the wire went into the plastic snap connector fitting(cant think of the term) it was not seated all the way. Once in a while it would lose connectivity and sputter. It acted like a "short". I do remember it was absolute luck that we found it!

gee a cap and rotor sure is cheap and they do go bad

Luch plugs, wires, cap & rotor would be my first move.

They are standard Ford automotive parts on the GT40.

There is a after market scanner available for the Gt40 that is very cheap. Probably cheaper than any of the tune up parts.


EEC1V Code Reader Scanner

Gary I think most of the quality dizzy caps are still brass terminals. I purchased a Accel cap and rotor kit for mine it has the rubber cap next to number 1 like you described.

Luch another thought with all this talk of distributor caps have a look inside dissy. Give the stator (PIP hall effect sensor) assembly a twist and see if it moves the plastic gets brittle and breaks down over time.

lewy2001 wrote: Gary I think most of the quality dizzy caps are still brass terminals.

the Motorcraft oem's are aluminium Mark,anywhere to save a penny. Kap,I think a fuel injected Ford 5.0 (302) of 1990-1993 vintage uses the same cap if you have those there

8122pbrainard wrote: Mark, What's the "PIP"? I'm only familiar with PNP and NPN. I tried looking up the PIP and couldn't find anything.

Profile Ignition Pickup (PIP) a PCM GT40 terminolgy not a electrical acronym. The GT40 uses a hall effect sensor and a slotted cup on the distributor shaft to determine crankshaft position and rpms.

lewy2001 wrote: Luch another thought with all this talk of distributor caps have a look inside dissy. Give the stator (PIP hall effect sensor) assembly a twist and see if it moves the plastic gets brittle and breaks down over time.

Dead on!!!! managed to fix the stator in position and boat pèrformed great all day.
No doubt this should go in the GT40 chart. Thanks Lewy!

Thanks to all for the advise given as well.

Bri892001 wrote: So, is the fix to replace the PIP, replace the dizzy, or just figure out some way to secure the PIP in place?

In my case, just fixing the stator into position solved the issue.

Ok cool.

Just wanted to add that locking the stator in place also solved a jumping tachometer that i've experienced since owning the boat,

Keuka 95 GT40 wrote: Hi Luchog - just reading this post and want to clarify the fix you used.   I have a 1995 GT40 with very similar problems last summer. Boat runs great most of the time but occasionally it will miss-fire and hesitate after pulling first 2-3 sets of the day. So "fixing the stator into position" solved the problem ?

In my case it did. But the failure was consistant. Have you done a complete tune up?

a complete tune up has not been done in several years. I will need to check with my father on dates of service. Any recommendations on what should be addressed in a complete tune up ?

My family has been on the lake for over 40 years. We are spread around the northeast now but Keuka is always the destination of choice over the summer.