Onan 7.5 Gen set

guglielmo6160 · Post by **guglielmo6160** » Mon Dec 17, 2012 11:54 am

not to keep beating a dead horse, but I came across this today at a garage sale near my house today, it has only surface rust, and looks ugly, but
it runs smooth and seems to work correctly , it starts right up and I put as many loads on it as I could find, and it seems to power them all up with ease.
I know its an older model, but I think I can get it at a more than fair price.
what do you guys think something like this could be worth in todays market?
If I buy it, I wll of course go over all the clamps, gaskets etc, and then a nice coat of marine paint, at the least.
it came out of a 50 Hatteras or so I was told.
thanks in advance

prowlersfish · Post by **prowlersfish** » Mon Dec 17, 2012 12:14 pm

Lets start off with the Bad . that is ugly . But I have seen many look even worse run for years . If runs good and the price right I would go for it ( make sure it will fit ) I don't have a clue what they are worth .

BTW rustolum paint works well

Big D · Post by **Big D** » Mon Dec 17, 2012 12:40 pm

I have a couple of things to consider;
- the heat exchanger of course is not OEM so you may want to ensure it's doing its job properly
- this older model does not have a starter, it uses one of the generator windings to start the engine. These typically take more battery power and longer to start - needs a good battery
- the exhaust elbow doesn't have the mount for a thermal cut-out switch to shut her down should the elbow heat up due to water pump failure. Same as the other that should currently be mounted to the head. This would not be difficult to add
- if you get this one, you should also replace the nipple between the exhaust manifold and the elbow. It looks like the original and should have been replaced with a stainless steel one due to a recall many years ago.***this is something everyone should be checking for as it is a safety issue; it was to replace the original that would rot inside-out, leak exhaust into the compartment and was apparently resposible for fatalities. Last I checked, the replacement SS nipple is still available. You'll need to heat the old one to get it off.

Stripermann2 · Post by **Stripermann2** » Mon Dec 17, 2012 1:37 pm

Sounds like a good deal.
I doubt it came from a 50ish Hatteras as it most likely would have been a diesel gen set...

Commissionpoint · Post by **Commissionpoint** » Mon Dec 17, 2012 2:57 pm

+1 what Jamie said about probably not being off anything as big as 50 feet.

+1 what Big D said about the SS replacement nipple.

+1 what Prowlersfish said about its ugly but thats ok.

Gas unit from late 70's/ early 80's. Probably spec H just from looking at it, maybe 1 spec later. A good unit if it runs well.

One other thing to consider is that if that exhaust manifold is on its way out you should probably look at a different unit. They are $$$$$$!!!!

guglielmo6160 · Post by **guglielmo6160** » Mon Dec 17, 2012 4:13 pm

thanks for all the good info ,
I will make certain I look into all those items,
the gen works , and it runs perfectly ,
it is not without issues,
1st
it needs a 12 v solenoid , for sure, you have to jump the solenoid to fire it off
2nd i
it needs the rocker start /stop switch, replaced, dosent run unless you hold it in the start position,
3rd
raw water impeller ,obvious reasons,
4th , a serious cleaning and a Rustoleum treadtment, including all clamps, replaced and updated to SS, and all hoses as well.
the exhaust manifold appears to be fine, with the exception of the nipple as Big D pointed out, in fact the seller did mention something about that,but he didnt know the particulars, details etc
the heat exchanger is not original , as pointed out, however it appears to be fine, with the exception of the way its mounted, looks like crap, but in excellent condition with no leaks,
Ill work my magic with the cosmetics, in time.
Im aware of the lack of a conventional starter motor, it turns over fine with a small automotive battery, so I dont see an issue with a deep cycle marine set up

Im going to try to write down all the info on this bad boy, so I can call onan or a parts distributor to get started on getting the parts,
I also want to change out some diodes I see under the access cover that look Fugazy.
The whole unit needs to be Guglielmoized in a big way,,,,,

and I bought it for 300 bucks
so I have room for repairs and updating, I think the price was right, from what I have been reading and looking at,

Big D · Post by **Big D** » Mon Dec 17, 2012 5:18 pm

Forgot to mention that you should check the type of choke you're dealing with and ensure it works, if it's the older style with a solenoid and the heating element has failed, it is a very expensive replacement. Also check to see if the t-stats are actually still there. Is there a data plate mounted on the unit?

guglielmo6160 · Post by **guglielmo6160** » Mon Dec 17, 2012 7:00 pm

no I dont see a data plate, that was my next question,
how can I find out what type of gen it is? year model etc
is there a good source for parts ?
thanks

Commissionpoint · Post by **Commissionpoint** » Mon Dec 17, 2012 7:04 pm

guglielmo6160 wrote:and I bought it for 300 bucks
so I have room for repairs and updating, I think the price was right, from what I have been reading and looking at,

Bang. Theres the answer right there. 300 smackers. Good work my friend.

You get that bad boy cleaned up and 'Guglielmoized' (If I'm right thats something like new parts, some paint, and a tune-up) and you will good to go.

Commissionpoint · Post by **Commissionpoint** » Mon Dec 17, 2012 7:12 pm

guglielmo6160 wrote:no I dont see a data plate, that was my next question,
how can I find out what type of gen it is? year model etc
is there a good source for parts ?
thanks

Need to know what model and spec it is to get parts properly.

I think its a 1982ish 6MCCK, Spec J now that I look at your picture more. Gonna need a little more than one pic to be sure though.

Can you find a serial number on it?

alexander38 · Post by **alexander38** » Mon Dec 17, 2012 7:22 pm

for $300 you be right if it runs 3 yrs....good buy ! As far as the switch check the fuse's make sure they're making contact and doing their job. When your looking for parts try this.

http://www.jackssmallengines.com/ also E-bay.

Lots of RV cck parts fit mcck Onans, the site Smokestack is also a great place for info.

Big D · Post by **Big D** » Mon Dec 17, 2012 7:27 pm

You may not be able to see it with the heat exchanger there but on top of the block next to the threaded hole where the lifting eye gets mounted, there is a small rectangular raised cast section close to the points box I think with a block serial number stamped on it.

guglielmo6160 · Post by **guglielmo6160** » Mon Dec 17, 2012 7:54 pm

Ive already started messing with it, and this I already know
I went to West Marine and picked up a starter relay and a rocker switch, the switch was broken, and the relay was not working at all. The gen starts and runs fine, as long as I hold the rocker switch in the start position. If I let it go back to neutral position it shuts down. Apparently there is a prob. From what I've read, could be a lot of things, It does make electricity, but I dont know if Im going to damage it running it that way while I t shoot it, as the relay is of course energized. I had my buddy holding the switch and I was able to plug in all kinds of high load items and it didn t even flinch. But Im thinking this is some type of low oil cutoff, sensor, etc, something like that. As far as the choke is concerned, I dont think that works correctly either,, I have to "prime " it to start, then of course once thats done it runs fine. Im currently running it on an electric fuel pump, (low psi) .and it will crank and crank cold until I prime it. So thats another issue. All in all its a good deal and will work on it until its working correctly and can be dependable. Im going to look tomorrow for a serial number so I can start the ball rolling,

prowlersfish · Post by **prowlersfish** » Mon Dec 17, 2012 8:14 pm

Big D , On the recall I was not aware onan had one on the exhust . I Do Know kohler had one with that issue .

http://my.boatus.com/consumer/Kohler.asp

prowlersfish · Post by **prowlersfish** » Mon Dec 17, 2012 10:04 pm

I did find a lot of complants on the Onan for this issue at boatus in a memebers only area ( no reprint alowed )