Onan MCCK 6.5 troubles

[onanboat]

This is my first post.

I am admitting this right away. I have never had an Onan 6.5 MCCK before. I now have one and I am trying to work out its bugs before I put it in the boat... It is raw water cooled.

I got it from facebook marketplace, and I was told it had a new carb, new plugs and was tuned. Seemed to check out. Carb looks new, plugs look new etc. However, I really don't know its history. It had service tags on it, and the price was right, and the oil looked clean.

I changed the oil, hooked up a battery, put some fuel to it.. it turned over, but could not get it started.

Checked the spark (had spark), checked timing according to the manual, and fuel was getting to the carb.

It turned over but had a dead spot.

A) First, repair. ...Replaced starter motor.

Now it starts, and runs.. runs good. However-- not pumping any water.

Because the cooling system was not working, I did not want to run it long, but I could start it, and stop it, and start it again.. NO PROBLEM.

B) Second repair. Replaced impeller (the original was all torn up) on the raw water pump, and replaced all the hoses, some of the hoses had sediment in them.

Now it is running and cooling great, pumping plenty of water....

However, I let it run for about 15 minutes, and then I manually turned it off. I tried to turn it back on.. NO LUCK.

NO FUEL is getting to the carb from the pump.

If I pour a little fuel in the carb manually. starts and then dies.. because no fuel.

C) I clean fuel filter. The fuel filter was dirty, and had a rusty colored dirt in it. However, even after cleaned, the fuel pump was still not pulling any fuel. I put my thumb over the fuel line at the end of the fuel hose I was using for the pickup, and I can feel a slight pumping action, but it is weak.

THREE HOURS PASS.

Now it starts up. But, its late at night, and I have neighbors. So, I can only run it for a minute or two, and I turn it off.. However, I can turn it on again after its turned off.

WHERE AM I NOW...

Tomorrow I will run it again for maybe 15 minutes, and see what happens after I turn it off... see if it will restart.

I am thinking the fuel pump is on its way out. I have seen posts on line where people replace the fuel pump with one from FACET. Can someone tell me the right one to get? I have seen ones with about 5psi or less... and I see bigger ones. I don't want to throw parts at this without knowing I need them, but I also don't want this breaking when its in the boat, and I have to pull this out of the boat (after installing it) to fix it.

I have also read that there are two temperature sensors that go to the elbow of the exhaust. Do those temperature sensors disable the spark, fuel or starter motor if the generator gets too hot?

Thank you for your patience. This is my first Onan so please be patient with me if I am doing anything way out of wack.  

Please, let me know your thoughts on how I can better diagnose this, and anything I should consider beyond replacing the fuel pump.

Harry

[prowlersfish]

Give Bob a call at BEACON MARINE @ 609-713-4602. He knows these Generators well and has the parts too.

[BeaconMarineBob]

Yes we can help we stock ever part for the Onan MCCK
Be advised lots of knock off fuel pumps from China.

Beacon Marine
609 713 4602

[onanboat]

Ok, I spoke to Bob.. turns out fuel pump is not pumping... ordered a new fuel pump.

The Journey continues.

[mrrudely]

Finally I may have some useful information.

I have a 4mcck and have been fighting with it for years.
I think I finally have it dialed in.

Mine has 3 sensors, oil pressure, block temperature, exhaust temperature,
if there is a problem with any one it will shut down the ignition.
BTW I recently chased a problem that I thought was the fuel pump
still not 100% sure but seems like it turned out to be a loose wire at the exhaust sensor.

I would not run it dry, the raw water impeller can burn up quickly.

I'm guessing the 6.5 is the same as the 4 with respect to an external battery
charger. Bob told me this as well as a few others, if you run an external battery
charger while the genset is running you can burn up the fuel pump, as crazy as that may sound.
You need a dedicated start battery for the genset without an external charger or if you have
a charger hooked up make sure it is off when the genset is running

Also I found some Onan parts to be ridiculously expensive, there are many other sources for parts.

Hope that helps
rr