Carver Owners Forum

Well, I did it again. Last time we were out, I made the comment about how well the genny had been running all summer. This week.... yup.

A solid no start condition. Cranks, but does not fire. No cough, no attempt at start, nada, nothing. Simply spins at a normal sound that it always had. (I've already pulled the drain plug on the water lift muffler so that I will not waterlock it while trouble shooting)

The patient, a 7.3 Kohler carb genny.

Oil full.
Coolant full
Port fuel tank at 3/4 (genny draws from port)
Impeller intact, water pumping through to muffler, (and currently draining out of muffler)

Replaced plugs (don't remember doing the annual plug change ritual this spring)
Check for spark at plugs, both have spark.
Pulled fuel hose off output side of genny fuel pump, no fuel while cranking. So that's a problem.
Check for power going to pump while cranking, no power on multi meter. I would think that's a problem.

Questions, I suspect whatever drives the pump (the dreaded board in the controller on the genny, or a possibility of a fuel pump problem since I'm not sure what I should get out of the plug to the pump, I would assume 12 VDC. I did not check to see if the transfer pump was moving fuel to the genny pump, nor did I remove the fuel filter that is upstream from the genny fuel pump. I stopped when I found no power to the pump. I'm kind of in the process to try to find a "proper" test of power to the pump.

Other suggestions?

Thanks

Bob!

Bad luck......Bob do you have the wiring schematic ?

I would think the pump would have a fuse and also a relay in the circuit somewhere. There might also be something that ties into oil pressure (but gets bypassed when cranking) so the fuel pump dies if there isn't sufficient oil pressure. Circuit diagram would be your friend, for sure.

The fuel pump shares the same fuse and relay as the ignition, so if you have spark, they should be fine. Check the 2 conductor plug at the fuel pump, I have seen them corroded enough that no voltage would pass. Separately power up the fuel pump and see that it works.

Keith S wrote:Source of the post The fuel pump shares the same fuse and relay as the ignition, so if you have spark, they should be fine. Check the 2 conductor plug at the fuel pump, I have seen them corroded enough that no voltage would pass. Separately power up the fuel pump and see that it works.

Well, I went back in during this weekend to have another look. I was prepared to jumper some power to the pump and see if I had flow. However as an additional test I decided to probe the plug again and see if there was power to the pump. There was. I have no idea why I didn't have power the other day, possibly I was grumpy and measuring the wrong end of the plug, or probably I had the meter on the wrong setting, (I don't use the boat's multi meter near as much as I use my work one... )

Anyway... a new pump is on order, we will see what happens!

Check temp shut off switch. There's two. One on top of each cylinder. Disconnect and try starting...

If the 12vdc polarity is wrong to the fuel pump, it will run backwards and not pump fuel. Just something to check before replacing the pump.

Difficult to reverse polarity on that model, 2-pin plug that only goes one way. Not impossible, but difficult. The electric fuel pump is a fairly common failure item. I change a dozen every year and keep 2 on the shelf.

I'm on my way down now (well... after I finish my coffee) with pump in hand to put that to the test!

The plan was delayed by the apparent need to pull up a bunch of fence posts out of the yard. Then off to the boat.

It was the pump. A new pump and filter later, it roars to life and settles down again like a normal genny should. Happy now, off to enjoy tomorrow with AC and all the goodies that go along with it. It's not so much as needing it, it just annoys me when something is down. Much happier boat (and crew!) when all is well.

Side note. In my searching for the pump, I found the same model number as an automotive application. (for half price of course) I did get the marine version, but upon removal of my old one, I see the sticker on the old one stating an automotive. It was painted over white as the rest of the genny. I do not know if it was original or not, (I seriously doubt it) but figure more likely that it was purchased and then painted as a replacement.