Genny raw water flow

[Hatadoit]

Hi,

I've got a 41TC with a onan 6mdjb genny. How much water should be coming out the exhaust? Should it be a stream (like the AC or bilge pumps) or just a spray (the exhaust is just barley above the water line, so it sort of spits when it's running).

Thanks,
Bruce.

[Pascal]

i'd say strong spitting is the best way to describe it... it's the exhaust pressure in the water lift muffler that pushes the water out so there is some pressure, unlike the Air con flow.

[Jaxfishgyd]

Spitting is the perfect term...

I have a 9 kw genset and it loves to spit, guess it shoots out about a a foot of water.

Matter of fact, has anyone seen a genset put out a stream like an A/C unit?

[(Nobody You Know)]

Not sure what the real concern is here. Do you think it's overheating? Most all put out exhaust water in spurts.

A laser hand held thermometer will go a long way in telling you if all components including the exhaust manifold are operating at the right temperature. They are pretty reasonable Granger Industrial Supply stores. (assuming like other Onans they have no temp gauge).

[Hatadoit]

My concern is that there isn't enough raw water flowing. The engine runs like a clock for about 7-8 mins and then quits. It won't restart for a couple of hours. I can lift the stop solenoid and get it goin' again, so I assume that the high temp sensor is doing it's job. Since this is my first genny I don't know what it's supposed to be like.

It sounds like I'm getting the correct flow out of it, so I have to look elsewhere. I've replaced the raw water impeller, inspected the coolant impeller, and flushed the cooling system. The expansion tank appears pretty clean. The oil pressure gauge seems to operate correctly and is within spec. The confusing part is that I can still lay my hand on the engine after it quits.

Any ideas? Thanks for the comments.
Bruce.

[clark leighs]

Maybe the alarm sensor is goofy. It won't be the first time a sensor has failed and caused nuisance shutdowns.
Try installing a temp guage in the water flow or try an I.R. laser thermometer.

If you can hold your hand on it then I'd be suspicious of the sensor. This is not a foolproof check but a good guide.

[Pascal]

an IR thermometer is a must have tool on a boat... make sure that your are really running hot, nothing ruins your day like spending hours troubleshooting a problem that doesn't exist

[Will]

A number of things can cause your problems i.e. low oil pressure, clogged fuel filters, faulty fuel solenoid, oil pressure switch, temp. switch, corroded electrical connections, etc. From what you say, it looks like coolant temp. is OK. Fuel filter problems often cause the engine to misfire or sputter a bit before shutting down. You probably have an electrical problem - bad sensor switch or connection.
Will

[yachtsmanbill]

The temp shut down switch is on the block just in front of the control box on the generator. Two wires to it. Jumper it out and test run it. That will tell you if the switch is bad.
There is a sea water flow switch on the after side of the SW pump. It has points that need to be set, and / or cleaned. It has a small oblong tin cover on it.
Below and between the oil filter and the primary fuel filter and below the injection pump is the oil pressure switch. You can jumper any of these, but that doesnt mean there isnt a problem with what they are reading. ALL of these are interlocked with the shut down solenoid. That has two integral coils in it. One is for BYPASSING all the safety shutdowns to start, then once oil pressure is up it will hold open and allow the unit to run. The other coil is for shutdown. ws