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1976 PK losing power when I mow


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#1 todapuckett ONLINE  

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Posted June 26, 2016 - 08:40 PM

Hi all.  I just purchased a 1976 Economy Power King tractor and I love it.  I am having a problem with it bogging down and losing power after about an hour of operating.  I have cleaned the engine, have replaced the battery terminals (battery isn't charging well but it is old and needs to be replaced), have adjusted the carb, and have put some Stabil in the gas because I can't get ethanol free gas.  

 

I think it is overheating, if that is the case I can take a break, but I don't think it should be doing it.  I am in North Carolina, and it is HOT and humid here.  Any ideas?

 



#2 olcowhand ONLINE  

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Posted June 26, 2016 - 08:48 PM

Could be valve clearances are too tight.  The hotter the engine gets, the tighter the valve clearances.  If too tight, they can actually dump enough compression to kill the engine.  This can also lead to burning a valve face or seat.  But also make sure the engine cooling fins are clear of debris.  


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#3 Alc ONLINE  

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Posted June 26, 2016 - 08:52 PM

Welcome to GTTalk ! It might help if you say which engine is on your PK in case there are some special issues
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#4 JBRamsey OFFLINE  

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Posted June 26, 2016 - 09:24 PM

You said you cleaned the engine. Did you pull the sheet metal off of the engine when you cleaned it? If not, I would do that sooner rather than later.

Make sure the carb is adjusted properly, too.
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#5 MNGB ONLINE  

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Posted June 27, 2016 - 02:53 PM

As posted what engine is in the tractor, does it have points & condenser or is it an electronic system, just what do you mean when saying it bogs down does it miss backfire or just lose Rpm's? How is the fuel filter have you changed it, does it have an original PK gas cap om the tank (could be that its not venting) you say you adjusted the carb what did you do?



#6 todapuckett ONLINE  

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Posted June 28, 2016 - 10:13 PM

Thanks for the responses.  The engine is a K321  14hp.  I pulled the top shroud and cleaned the engine cooling fins, haven't pulled the sheet metal around the side.  It is an electronic system, no points or condenser.  It is the original PK gas cap, but I don't think the vent is clogged since it runs great for an hour or so.  I adjusted the carb according to the Kohler manual, probably need to run it a little richer.

 

It doesn't miss or backfire, just loses RPM's. 



#7 todapuckett ONLINE  

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Posted June 28, 2016 - 10:15 PM

I will pull ALL the sheet metal off the engine and make sure there isn't anything hiding in there and see how that does


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#8 Alc ONLINE  

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Posted June 29, 2016 - 05:40 AM

You mentioned that it isn't charging well , what do you mean by that ?  Might want to check the battery voltage when the problems happens . Still would clean everything first . I made a tool for getting into small spots by attaching a steel brake line to my air blow gun  . you can bend to get in places around things



#9 todapuckett ONLINE  

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Posted July 12, 2016 - 09:16 PM

UPDATE:  I pulled the cooling tins off and the engine was clean, but I did scrape out the cooling fins to make sure.  Still lost power and finally died.  I wasn't getting fuel.  Bypassed the fuel pump and ran it as gravity feed and it cranked and ran.  I replaced the fuel pump with a new plastic one, which promptly broke.  The pump arm cracked, I am 99.9% certain I had the arm on top of the cam as instructed, the new plastic pumps are cheap.  I rebuilt the old metal pump using a kit I ordered from here http://www.then-now.com/ (great product, great service, highly recommend them) and hoped I had the problem fixed.  Nope, same thing ran great for a while then lost power.

 

So, pulled the carb and opened the valve cover and the valves were WAY out of adjustment.  Intake barely had .002, don't know what exhaust had because I started adjusting before I thought to check, but it wasn't probably .007 at the most.  So, hopefully the valve cover gaskets and carb rebuild kit will be delivered tomorrow, I figured while I the carb off I may as well clean and rebuild it as well.  I will let everyone know how it is running once it is back together, but I am pretty certain the valves were the problem. 


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#10 Alc ONLINE  

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Posted July 13, 2016 - 06:20 AM

Hope the valve adjustment will take care of your problem . Maybe it was dumb luck the fuel pump went out too .

#11 DougT ONLINE  

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Posted July 13, 2016 - 08:47 AM

Another thing with those engines is that the ignition module has to make a good ground at it's mounting.


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#12 todapuckett ONLINE  

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Posted September 02, 2016 - 09:34 PM

20160902_174448.jpg 20160902_174520.jpg

 

Pulled the head


Edited by todapuckett, September 02, 2016 - 09:37 PM.


#13 todapuckett ONLINE  

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Posted September 02, 2016 - 09:37 PM

Still having trouble keeping it running.  I did get some trash out of the gas tank, but that didn't fix it.  I have adjusted the governor, and the carb, still won't run under load.  I pulled the carb back off and am soaking it in cleaner now hoping there is something in a jet.  I also pulled the head to clean the carbon out.  This is my first time in this engine, want y'alls opinion on how this looks. It is pretty much what I was expecting



#14 MNGB ONLINE  

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Posted September 02, 2016 - 10:13 PM

Hi, so what is happening when the engine is  under load? The pix look pretty normal for a engine that has time on it.



#15 classic ONLINE  

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Posted September 03, 2016 - 10:18 AM

Your head gasket looks like it's leaking. You should tape a piece of sandpaper to a piece of glass or known flat surface and sand the head surface until it's flat. Reinstall with a new head gasket. Take a pic looking straight down into the bore. I've seen flat spots on the sides of Kohler pistons that have a lot of hours on them.
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