6.5 onan genny mcck fuel issue

sluggo · Post by **sluggo** » Thu Sep 20, 2012 3:48 pm

My genny is getting close to genning again, but I have a hard time keeping it running. We are pretty sure it is a fuel issue, as we have cleaned out the realively new carb, several times. Each time it has the 'gunk' assoicated with the ethonal gas in it. I have changed the filter on the fuel pump as well as the element in the fuel/water seperator. Any other ideas. I have put in the Starbright greeen stuff in the fuel each time I fill up. thanks!
I have a new (this month) thermal cut off switch on it as well.

Commissionpoint · Post by **Commissionpoint** » Thu Sep 20, 2012 11:08 pm

I put a new fuel pump on my MCCK this season. I used a Facet, which was OE for my spec J set, but I got it from Facet and not Onan which saved some loot. (a lot of loot actually)

Seemingly the old pumps will still move fuel, but not at the proper pressure when they get old and you get random shutdowns that might make you think thermal switch. I know thats what I was thinking, but a buddy who is a generator geek said it was probably the pump, and he was right. You too may want to look into that. The pump cost me about 80 bux and took less than an hour to swap out despite its crappy location. Since then I get no more unwanted random shutdowns.

Good luck sorting it.

sluggo · Post by **sluggo** » Fri Sep 21, 2012 10:29 am

Commissionpoint wrote:I put a new fuel pump on my MCCK this season. I used a Facet, which was OE for my spec J set, but I got it from Facet and not Onan which saved some loot. (a lot of loot actually)

Seemingly the old pumps will still move fuel, but not at the proper pressure when they get old and you get random shutdowns that might make you think thermal switch. I know thats what I was thinking, but a buddy who is a generator geek said it was probably the pump, and he was right. You too may want to look into that. The pump cost me about 80 bux and took less than an hour to swap out despite its crappy location. Since then I get no more unwanted random shutdowns.

Good luck sorting it.

thanks I might do that, there is a Facet pump on there now, but it has to over 10 yrs old (I've owned the boat that long and never replaced it)
do you know the #/model you used from facet? or the spec I need?

Commissionpoint · Post by **Commissionpoint** » Fri Sep 21, 2012 12:53 pm

https://www.pegasusautoracing.com/produ ... RecID=2698

sluggo · Post by **sluggo** » Fri Sep 21, 2012 1:01 pm

Commissionpoint wrote:https://www.pegasusautoracing.com/produ ... RecID=2698

thanks, I think I may have circled another one from this site to buy if need be, so you are sure of the specs on this (best you know) for an 87onan mcck genny. double thanks!

Commissionpoint · Post by **Commissionpoint** » Sat Sep 22, 2012 12:15 am

sluggo wrote:
Commissionpoint wrote:https://www.pegasusautoracing.com/produ ... RecID=2698
, so you are sure of the specs on this (best you know) for an 87onan mcck genny. double thanks!

I'll be quite honest with you. I can work on anything, and I can make just about anything run. No bull. That being said, Onan MCCK's are a PITA! Not kidding. They are ornery, unconventional, and costly to maintain if you buy factory parts.

What I know is that the pump I linked on that post is the one that was the direct replacement for my Spec J MCCK. I dunno what spec your 1987 model is. THIS MEANS ALOT. I cannot place enough emphasis on this. Over the years as new variants of the same model were produced the spec type was changed to signify the update in production. Different parts were used on different spec models. What I DO know is that below spec J was a different pump. I also know that on the page I linked to you there is a tool for finding the Facet part #on your pump to make sure you get the proper replacement part.

I hope that helps. Personally I'd love a Westerbeke, but I won't be buying one anytime soon. That is my ultimate solution to the Onan though.

aaronbocknek · Post by **aaronbocknek** » Sat Sep 22, 2012 9:54 am

Commissionpoint wrote:
sluggo wrote:
Commissionpoint wrote:https://www.pegasusautoracing.com/produ ... RecID=2698
, so you are sure of the specs on this (best you know) for an 87onan mcck genny. double thanks!
I'll be quite honest with you. I can work on anything, and I can make just about anything run. No bull. That being said, Onan MCCK's are a PITA! Not kidding. They are ornery, unconventional, and costly to maintain if you buy factory parts.

What I know is that the pump I linked on that post is the one that was the direct replacement for my Spec J MCCK. I dunno what spec your 1987 model is. THIS MEANS ALOT. I cannot place enough emphasis on this. Over the years as new variants of the same model were produced the spec type was changed to signify the update in production. Different parts were used on different spec models. What I DO know is that below spec J was a different pump. I also know that on the page I linked to you there is a tool for finding the Facet part #on your pump to make sure you get the proper replacement part.

I hope that helps. Personally I'd love a Westerbeke, but I won't be buying one anytime soon. That is my ultimate solution to the Onan though.

having grown up with a kohler 7.5 on our tri cabin, i can only agree that the onans, while usually reliable, they are NOT diy friendly. the kohler was so easy to maintain it was almost dummy proof. standard spark plug wires, standard oil filters, everything within easy reach to replace. BELIEVE ME, if i had the $$ i'd swap out my onan for a kohler or a westerbeke in a heartbeat. if i did, i'd go from 6.5 to 7 or 8kw.

prowlersfish · Post by **prowlersfish** » Sat Sep 22, 2012 11:26 am

Say what you will , but there is something to be said when a Onan is having minor issues and they are in many cases 35-40 years old . and there are a ton of them out there at that age . I wonder if my genset will last that long ? I don't think I will live that long to find out .

Big D · Post by **Big D** » Sat Sep 22, 2012 12:22 pm

IMO, the Onan isn't really that hard to work on. Pretty simple engine and generator actually. Gotta remember when these were first built/designed, they made them to last. Quite frankly, they're bullet proof. Still a lot of original units out there powering commercial stanby systems first installed long before they made thier way into boats. Why don't they upgrade to newer gensets? no need to! They're pretty hard to kill unless of course they don't get used, but that will kill any engine. As far as parts go, yes some are hard to come by but think of thier age. I can name thousands of items built in the last 5 years that you can't get parts for anymore. Expensive parts? Yes. When you start using aircraft grade components at the time like shielded spark plug cables, plugs, etc. ya it can be pretty pricey but I'd put an old Onan up against some of the newer stuff any day. Is it the best ever made? maybe not, but I sure as hell am happy with the one I have, and I've worked on a few brands over the years. Once you understand their operation, I think they're a piece of cake.

sluggo · Post by **sluggo** » Sat Sep 22, 2012 2:02 pm

Commissionpoint wrote:
sluggo wrote:
Commissionpoint wrote:https://www.pegasusautoracing.com/produ ... RecID=2698
, so you are sure of the specs on this (best you know) for an 87onan mcck genny. double thanks!
I'll be quite honest with you. I can work on anything, and I can make just about anything run. No bull. That being said, Onan MCCK's are a PITA! Not kidding. They are ornery, unconventional, and costly to maintain if you buy factory parts.

What I know is that the pump I linked on that post is the one that was the direct replacement for my Spec J MCCK. I dunno what spec your 1987 model is. THIS MEANS ALOT. I cannot place enough emphasis on this. Over the years as new variants of the same model were produced the spec type was changed to signify the update in production. Different parts were used on different spec models. What I DO know is that below spec J was a different pump. I also know that on the page I linked to you there is a tool for finding the Facet part #on your pump to make sure you get the proper replacement part.

I hope that helps. Personally I'd love a Westerbeke, but I won't be buying one anytime soon. That is my ultimate solution to the Onan though.

thanks for your time and help!!!

sluggo · Post by **sluggo** » Sat Sep 22, 2012 2:04 pm

Commissionpoint wrote:
sluggo wrote:
Commissionpoint wrote:https://www.pegasusautoracing.com/produ ... RecID=2698
, so you are sure of the specs on this (best you know) for an 87onan mcck genny. double thanks!
I'll be quite honest with you. I can work on anything, and I can make just about anything run. No bull. That being said, Onan MCCK's are a PITA! Not kidding. They are ornery, unconventional, and costly to maintain if you buy factory parts.

What I know is that the pump I linked on that post is the one that was the direct replacement for my Spec J MCCK. I dunno what spec your 1987 model is. THIS MEANS ALOT. I cannot place enough emphasis on this. Over the years as new variants of the same model were produced the spec type was changed to signify the update in production. Different parts were used on different spec models. What I DO know is that below spec J was a different pump. I also know that on the page I linked to you there is a tool for finding the Facet part #on your pump to make sure you get the proper replacement part.

I hope that helps. Personally I'd love a Westerbeke, but I won't be buying one anytime soon. That is my ultimate solution to the Onan though.

thanks for your time and help!!!

Commissionpoint · Post by **Commissionpoint** » Sun Sep 23, 2012 12:14 am

Big D wrote:IMO, the Onan isn't really that hard to work on. Pretty simple engine and generator actually. Gotta remember when these were first built/designed, they made them to last. Quite frankly, they're bullet proof. Still a lot of original units out there powering commercial stanby systems first installed long before they made thier way into boats. Why don't they upgrade to newer gensets? no need to! They're pretty hard to kill unless of course they don't get used, but that will kill any engine. As far as parts go, yes some are hard to come by but think of thier age. I can name thousands of items built in the last 5 years that you can't get parts for anymore. Expensive parts? Yes. When you start using aircraft grade components at the time like shielded spark plug cables, plugs, etc. ya it can be pretty pricey but I'd put an old Onan up against some of the newer stuff any day. Is it the best ever made? maybe not, but I sure as hell am happy with the one I have, and I've worked on a few brands over the years. Once you understand their operation, I think they're a piece of cake.

Yeh sure, like anything I suppose. I build Mercedes engines in my spare time so I'm no stranger to one offs. Lets be honest though. Onans are overengineered. Its like my pair of w126's. If you want to work on them there is a matter of palatability. You have to have the money and either the willingness to learn or a mechanic you trust.

Other than that if you don't like Kohler or Westerbeke you can try your luck on a Northern Lights.

And thats all I am gonna say. YMMV.

prowlersfish · Post by **prowlersfish** » Sun Sep 23, 2012 9:50 am

The biggest issue I have had working on any gen-set be a Onan , westerbeake , Kohler or northern lights and others is the placement of it in the boat . And I have worked on all the above both gas and diesel . I have a northern lights myself , but if I had a gas boat I would be as happy with a onan as anything else , ( Nothern lights only makes Diesels gensets) .

Big D · Post by **Big D** » Sun Sep 23, 2012 4:42 pm

Ever have to repair a recent 6.5 Kohler in a box? Nice quiet little units in a small package/footprint but have you tried working on one? I'm talkin' tight!

prowlersfish · Post by **prowlersfish** » Sun Sep 23, 2012 5:45 pm

Big D wrote:Ever have to repair a recent 6.5 Kohler in a box? Nice quiet little units in a small package/footprint but have you tried working on one? I'm talkin' tight!

No fun at all .