GT-40 will not start after changing fuel filter

I would check and see if the low pressure fuel pump has voltage when you first turn on the key and if you do check the pump it's self. If it never has been changed it might be time they don't last forever. If it is bad check back there are alternative Carter pumps for a fraction of a PCM branded Carter pump

And Gary for checking the pump itself....how to do that? I think I know but...

Also, should I hear the low pressure fuel pump prime when I turn the ignition on?

Thanks for the replies. In the next couple of days I will go through some checks. I've been reading quite a bit here on the forums as to past problems/posts. One more thing, should you read this later, I did put the battery back in the boat today---- and also my ignition switch had loosened so I took off the 4 screws holding the instrument cover, pulled it out a little, and reached under the corner to tighten it.

Can't get volt reading at low pressure fuel pump.

Thanks again Gary. I will do that tomorrow.

Also just swapping one relay for the other won't tell you anything because you need 2 good relays to get power to the fuel pumps.

Power has to pass thru the EEC relay (#13) to actuate the fuel pump relay (#19) as you can see in the diagram below from an old Lewy2001 post

lewy2001 wrote: John this should clear it up a picture. Forgot I had uploaded this picture to site. Also just uploaded the fuel pump circuit diagram. This diagram shows the EEC computer wiring as well. If you do not know how to jumper the STO. Check it out in AMB's Fuel supply thread is on one of the early pages. The STO connector is that black shell marked EEC test covering the wiring connector next to the cct breakers and above the relays.

Sorry I have misinformed Gary/Keno, but I tried to hold my power meter and turn the key at the same time by myself initially.

Keno, yes the boat did briefly start and run after I messed under the dash. I did raise the dash, lay on my back, and check for anything like disconnects that I may have done tightening the key switch. Found nothing.

So yes power is to the low pressure fuel pump. But the fuel control cell will not fill.

If it didn't run, Gary's advice below sounds like a plan

At least you know your relays are good.

Too bad it wasn't a broken wire, it would have been easier and cheaper   

Gary S wrote: . As to the pump itself if it has voltage I would remove it and just try running it on the bench being careful about fuel and sparks not mixing well. Carter P4389 is a replacement which can be found for around 60 on the internet vs 212 for a PCM branded Carter pump

When power hits the low pressure pump it does work. So back to the relays...

When I turn the key power is coming in to the right relay on one of the 4 terminals. There is constant power at one other terminal out of the 4.

On the other relay there is power coming in at one terminal of the relay only. When the key is turned on power does not come to another one of the 4 relay terminals.

So when the key is turned if power is only supposed to come into one terminal of one relay as is the case with my situation, then it pretty much can be assumed (I am assuming/guessing here) that the relay is broken. If power is supposed to come into both relays when the key is turned then the problem is before the relay.

I would guess that key sourced power is only supposed to come to one relay and I can go get a replacement tomorrow.

Keno/Gary, do you guys have anything you can add? Thanks again.

Keno I have contradicted, sorry to have done that. But when I checked "the power" to the fuel pump I did get a reading, but in trying to both turn the key and hold the power meter contacts to the low pressure fuel pump I was not able to see precisely what the reading was. Evidently it wasn't anywhere close to 12 volts because the pump would not run. As soon as I did put a battery next to the pump and get two wires to it the thing worked perfectly.   So my posts about power getting to the pump were incorrect.

I will get two relays tomorrow. I appreciate the help. I have over the years gotten to know my boats pretty well, yet so much time passes (thankfully) between problems I often forget everything I evidently once knew fairly well a long time ago.

Be sure to do any electric fuel pump tests while the pump is hooked to fuel.   These are fuel lubricated pumps and can be damaged if run dry. In 10 seconds a pump motor can be damaged when run dry.

Gary/Keno/MrMcD I'd like to convey my thanks for your patient help . With the replacement of both...replacing either one only did not work...relays the boat immediately cranked up. Getting ready to shove it into the water. I find it hard thinking that both relays were bad but it looks like maybe that was the case.

My boat has the same relays, do they fail often? Are spares needed on board?
To date my engine has not missed a beat but it is 23 years old?
I do agree it is very odd they both failed at the same time maybe there was an electrical spike?
Glad you got it running and nice work once again Keno.
Mark

Always nice to see the positive outcomes from the brains of CCF. It’s what brought me to CCF and owning a Correct Craft boat.