5E Kohler

countrycoach15

I have a 5E Kohler  and it is over heating . I have replaced the heat exchanger, T-stat,water pump and cleaned out the strainer . I have used the 1/8 plug on the top to get all the air out of the coolant system and i have good water flow on the sea side . It runs perfect for about 5 min then starts getting angry and back fires and turns off . Heat exchanger is cool but the top by the rad. cap is not . Am I missing anything ?

Stodge

There is an impeller inside the genny motor that moves the water around.  Did you replace it?  

Dream_Inn

Well, you state you have good sea water flow.  My guess would be you are air locked on the coolant side.  What did you do when you used the 1/8 plug?  To get the air out, you have to have plug off, squeeze large back hose and hold, then tighten plug and release hose.  While doing this, make sure overflow tank has antifreeze in it and hose is all the to the bottom.

Black_Diamond

Dreams comment on the airlocking is correct. The 5e traps air in the coolant side and it will not self purge. 

Are you sure it is overheating?  The thermostat is ~190F so the area by the rad cap will be hot to the touch. 

Backfiring is usually due to running lean. Do you have the sound cover on yours?  Try running it without the cover service door/panel on. 

countrycoach15

I did replace the impeller for the sea water side is there one for the coolant side?

countrycoach15

I removed the plug , put an 1/8 nipple in and used a hand pump from an outboard and ran it to the over flow coolant tank . It seemed to work it really moved the coolant around quickly . Was that not correctly done ?

Stodge

countrycoach15 said:

I did replace the impeller for the sea water side is there one for the coolant side?

Yes it's inside the engine.  If your exchange is cool and engine is hot that's a good candidate.

Dream_Inn

countrycoach15 said:

I did replace the impeller for the sea water side is there one for the coolant side?

I believe the P/N for the closed coolant side is 359956 (you can search it on google for pictures of where it is).  But, I'd find it hard to believe that is the problem.  If it truly is overheating, you more than likely have an airlock.  I've gone thru the process and it takes a while to get it out.  The backfiring has my curiosity though that it could be something else.  I'd try what BD mentioned.

I found this in a earlier post (https://rinkerboats.vanillaforums.com/discussion/1883/kohler-5e-generator-please-help) by BD:

2. Replacing the thermostat almost certainly means you have trapped air in the system (a known problem with the 5e)...and it will overheat.  There is a bleed plug on top of the heat exchanger, but it still won't get all the air out.  I solved this by putting a1/8"NPT barbed hose connector, attached a hand type liquid pump so it pulled from the heat exchanger, leave the pressure ('radiator') cap on, fill the over flow bottle with antifreeze mix and start pumping (you want the suction side conneted to the barbed hose fitting).  As you pull a vacuum the air will pull out but be sure to NOT let the overflow bottle go empty as you do this. 

Stodge

@Dream_Inn I had the same overheating issue and it turned out to be the impeller.  

countrycoach15

the impeller on the coolant side ?

Stodge

countrycoach15 said:

the impeller on the coolant side ?

Yes, there is one inside the generator motor to circulate the coolant.  In my case, the pin that goes through the shaft had corroded to nothing so the shaft turned but the impeller just sat there.  

countrycoach15

could you advise where it was on your gen. please

Stodge

I had to have my mechanic fix it.  From what I understand the impeller is metal.  He described it as being "inside".  I don't think it's a very common problem.  But if nothing else pans out it would be worth a look.

Black_Diamond

That’s a job to get to the internal water pump. Seems super odd to corrode too!

I just do not connect the backfiring to overheating. An overtemp will shut the unit off, not run bad. 

countrycoach15

I am meeting with a gen. guy today . I will let you all know what he comes up with . Thanks for all the info!!!

Stodge

Black_Diamond said:

That’s a job to get to the internal water pump. Seems super odd to corrode too!

I just do not connect the backfiring to overheating. An overtemp will shut the unit off, not run bad. 

When I got the boat it was 12 years old and the genny only had 50 hours on it.  I don't think it was maintained the very best over those 12 years.

Dream_Inn

yes, the worst thing you can do to it is not use it!  50 hours in 12 years just means trouble.  Looking forward to hearing what the outcome is.

Black_Diamond

Have you put new plugs in it?  It will run on one cylinder till you load it up.  The 5e eats plugs. 

countrycoach15

UPDATE : I was off on what I was thinking on the gen overheating . It is running at 130 mark well for as long as it runs . So the guy that came down to fix the gen had no luck . He spent some time and didn't get it repaired . The only thing that he could guess it could be is the carb. so I have ordered a new one and see what happens . I'll keeping you updated.

Black_Diamond

Ah the 5e fun. 

I’d replace the plugs either way. Mind you there are 2!

there is an inline fuel filter that screws into the fuel pump, follow the fuel line and you’ll have to take the small cover off to get at it. Personally, I got rid of it. Put in a barbed adapter to accept the fuel line. Mind you I have a fuel filter inline by the fuel shut off valve too. 

Clean your spark arrestor. 

Run with the service door off of you have the sound enclosure. At least on mine, it gets air starved and quits with it on. 

countrycoach15

Thank you !! I have already bought new plugs i'm just waiting for the carb now . Did not know about the fuel filter I have a spin on fuel filter but i will look for another one by the pump and will clean the spark arrestor

Dude_Himself

While we're on the subject, any tips on doing the rear plug?

Black_Diamond

If you have the sound cover. Remove the two screws at each corner at the service door side. Then the 2 screws at the rop of the side panel at the carb end. Remove that panel. Whole top will tilt back. You can get the plug with a socket and ratchet...might need a universal joint. Bit of Helen Keller needed but easy once the cover allows your hand back there. 

Willhound

Wow. I often wish I had an on board generator. And if I had air conditioning it would be mandatory.  But I see so many issues with maintaining them that I'm glad I don't. 

Dream_Inn

Dude_Himself said:

While we're on the subject, any tips on doing the rear plug?

Obviously remove top cover, I can usually just push the back cover away.  Also a universal joint for the ratchet will help as well with an extension. 

Dude_Himself

Let me focus the help a bit: for anyone with a 270 or 280, any idea how to get to the rear spark plug? 

  

There's not much room to lift the cover off due to the cockpit sole. I'm tempted to add an access door through the midberth - that would make things simpler all around.

EDIT: about 5" from sound cover to ceiling of the engine "room".

Black_Diamond

Most all the genny issues are from it NOT being run. 

Spacelord

My genny ran fine for a while yesterday, I turned on the AC, then the battery charger for a few minutes.  I heard it go under load, let it run for a few minutes.  I flicked the battery charger breaker off and then the genny sputtered and stopped.  (strange timing maybe?)
Then when I tried to restart it took some trying to get going again, but was backfiring.   I am going to change the spark plug. .. as suggested here, on most every google search, and from a suggestion from someone at work.   I heard the plugs on Koeler gennys are best changed every year.

countrycoach15

Ok here is the update . I put a new carb and plugs on the gen and it runs perfect !!!

Praise the Lord

reneechris14

Awesome