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1969 Simplicity

Started by EZ, January 05, 2004, 05:38:38 PM

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EZ

My old garden tractor is a good old tractor, it mows grass perfect. But now I been having trouble with it. When it gets good and warm up it starts to miss and back fire. Its a 12 hp cast iron block which they dont make any more. It has plenty of power when it runs good when I first start it up. It dont use any oil, I put a new carb on, new coil, new plug, new points and condenser. But it still misses when it get warm up.
EZ

woodmills1

Maybe take a compression test, one cold one warm.
James Mills,Lovely wife,collect old tools,vacuuming fool,36 bdft/hr,oak paper cutter,ebonic yooper rapper nauga seller, Blue Ox? its not fast, 2 cat family, LT70,edger, 375 bd ft/hr, we like Bob,free heat,no oil 12 years,big splitter, baked stuffed lobster, still cuttin the logs dere IAM

Minnesota_boy

I've replaced a bad plug with a new bad plug and got the same symptoms.  Try another plug, maybe even a different brand of plug.
I eat a high-fiber diet.  Lots of sawdust!

ADfields

When was the last time you had the fan housing off it?   If you get poor cooling around the head from gunk in the fins will make it pre-ignite and do all kinds of odd stuff.   Cleanness in next to (insert divinity of choice)leeness. ;D   Also could be a bad plug or plug wire.  

Do you squint your eyes and stick your tong out the corner of your mouth right when you start it up? ;D :D :D :D  
Andy

Tom

Is a fuel solonoid something new?  I have one on the bottom of the bowl on my Kohler and it caused me all kinds of problems .... and  money.  It was bending push rods and the shops couldn't find the problem.  Finally, after spending several hundred dollars and using different shops I found one that diagnosed the fuel solonoid as bad and I've not had any problems since.  

EZ

I'll have to try a compression test. I've always used champion plugs, what type of plug do you guys use. Been a while since I clean the cooling fins, have to pull the motor to do that, but it probably would be worth it.
Tom, dont quite understand the fuel cell thingy. If your talking about a fuel pump, its gravity feed.
Wonder what the compression should be.
EZ

Tom

EZ
It may have happened later in years, but there was a fuel solonoid activated valve attached to the bowl of carburators with gravity feed to stop them from running on or loading up or emptying the tank when you stop.

I always thought it was a fix to cover up a failure instead of fixing the failure since that is the purpose of the float bowl.  Why add a doo ma flotchy to the float bowl because the float bowl doesn't work.  Any how, I just wanted to suggest it since it caused me so much trouble. It's probably something one of these new fangled engineers designed at the turn of the century. :-/

OneWithWood

EZ,
Is your throttle governed by a spring?  On my ancient Bolens with a Briggs cast iron engine the throttle had a spring loaded governor on it.  When it got warm it had the same simptons you describe.  I replaced the spring and all was good.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

VA-Sawyer

We used to use an "Air Horse" ( modified Wheel Horse ) to move airplanes. One day the engine started doing the same thing you are describing with yours. Turned out some one had added some Jet Fuel ( like kerosene ) to the tank.  That lowered the octane and caused pre-ignition.

I think your problem is the pre-ignition. Just don't know if it is bad fuel or overheating like ADfields suggested.

VA-Sawyer

ADfields

VA-Sawyer
Thats a great point about the fuel! ;)   We had good gas in 69 when it was made.   Put some supper in it and see if it just wants the good stuff.
Andy

EZ

I bought a new governor spring for it, no different. Compression is about 90. I try the high test last summer, no different.
Tom, no fuel cell, the gas line is a straight shot from the tank to the carb.
I called the dealer and he said it was the voltage regulater, said it was shorting out causing overcharge in batteria which is burning up the coil and points. I always thought if the batteria was being over charge it would blow up. O-well right now I'll try anything.
EZ

breederman

you may need to use some lead additive like we use in the old ford.It was built pre-unleaded gas.
Together we got this !

ADfields

That don't add up to me as you say the next time you run it the thing starts off good.   If you had an overcharge to the point it made a miss due to coil or points they would still be damaged after cooling off and likely not work enough that it would cold start. :-/   An over charged lead acid battery stinks like rotten eggs or stale dog farts and as such is hard to miss! :o   They will explode if you make a spark near them in that stink/air mix!!   I had one blow right in my face when jump starting a truck and using a Bic lighter as a flash light :o not a good plan! :-/   Thank God nun got in my eyes!!!
Andy

Lenny_M

I would try additive in the fuel, I`ve had similar problems with the older engines. 8N ford.320 john deere.old koller ect.
                                         Lenny_m

Furby

I was told the additive was to keep the valves from burning.  ???
I use it in the old wheel horse.

ADfields

QuoteI was told the additive was to keep the valves from burning.  ???


Thats what it's for.   Old valve seats were carbon steel that was soft when hot and the lead acted as a buffer for them, make them last longer.   Today we have better steels to use for valve seats and if you have the heads rebuilt and the seats replaced you no longer have a need the lead at all.   Old soft valve seats are few and far between today as they have a much shorter life then the new ones and have not ben produced for something like 30 years now.   But they can still be found in some things like a Ford 8-N or a Popping Johny or a 1969 garden tractor like we have hear.   A bad valve seal could very well make it do like it was described (run bad only after wormed up) but I think it's much more likely a pre-ignition case than any thing.
Andy

EZ

I did'nt buy a voltage reg. cause it kinda sounded far fect to me, besides that the Napa guy guy kinda look at me funny when I ask him about it. He said but I'll sell you one if you really want it.
Makes alot of sense about adding lead to the gas, but it mite be to late now, cause I been running it without lead for about 15 yrs.
I did do a compression check on it, like woodmill said, but I didnt check it warm. Its been 5 and 10 degrees here and it wont start. ::) Maybe after I get it started that warm up chech will tell all, I hope. I'll let you all know when I get it started.
Thanks
EZ

etat

Remove the head.  Scrape and clean off all the carbon built up on it over the years.  Clean around the valves.  Replace the headgasket.  Torque everything back down.  Carbon build up inside the head might be a part of the cause of preignition.  Also might not be allowing the valves to completely close. Just an idea. Also, are you sure you have the right carb?  A lot of the newer motors I've noticed miss a bit, until they are put in gear and running under a load.  I've noticed this on my lawnmower, and my garden tiller.  Have you tried adjusting the carb. at full throttle?  Is there a diaphram behind a plate on the valves, sometimes this can get a pinhole in it and cause problems. What about the rubberhose that attaches to it and the carb, it can develope an air leak.  Is the gasket between the carb and the block sealed really well, sometimes an air leak there will cause problems.
Old Age and Treachery will outperform Youth and Inexperence. The thing is, getting older is starting to be painful.

woodmills1

I am assuming it is a one cylinder engine so you don't have any comparison for compression.  Since you got 90 cold now check it hot to see if it drops off.  My thoughts are that it might, could be cylinder wear or valve that doesn't seal when hot or something like that.  If I remember old timers would shoot some oil into a cylinder with low compression and if that caused a higher reading they new it was piston related rather than valve related.
James Mills,Lovely wife,collect old tools,vacuuming fool,36 bdft/hr,oak paper cutter,ebonic yooper rapper nauga seller, Blue Ox? its not fast, 2 cat family, LT70,edger, 375 bd ft/hr, we like Bob,free heat,no oil 12 years,big splitter, baked stuffed lobster, still cuttin the logs dere IAM

Tagerts_crossing

  All the responses are good things to check, but my first guess would be the ignition breaking down when hot.  This seems to happen to me from time to time.     JOHN
John Schoolcraft

Fla._Deadheader

  Sorry guys, gotta agree with AD on this one. My daughter tried to burn ours up EXACTLY the same way. Too much dead grass in the cooling fins. It will definitely cause the problems that EZ has. ;D ;D ;D    EZ, get your blade yet??? I gotta call and get some more and I want an explanation why you haven't received yours  >:( >:( >:(
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

EZ

I'm going to have to pull the motor off to clean the air flow so I my as will pull the head and check for carbon build up.
To many pots on the stove right now. I'm getting real close in finishing my mill, so that is the first thing I want to do.

No blade yet F,D.
EZ

dutchman

Two years ago rebuilt a @ 1965, 8 HP Kohler motor.Ran for about 2 hrs.got hot and would miss.Cylinder was out of round, and tapered a couple thousands toward the top of the cylinder.Rebuilt with an oversize kit, runs
better now than it has for years.

EZ

I hope it dont need overhauled. I bought a new 11 hp for it but would like to save that for another project. Dont really want to put any more money in it, right now.
Besides I'll have to save my money for some of them new Monkey saver blades.  ;D
EZ

ADfields

DanG Harold, you make it sound like your shocked that "I" could be right. :'(                :D :D :D
Andy

Fla._Deadheader

No way, Andy. I wuz agreein with ya ;D ;D :D
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

etat

You say it runs good when you first start it up.  How long before it runs and warms up enough to start cutting out and backfiring ?


If you do remove the head when you replace the head gasket if you spray it with aluminum spray paint it will seal better.  The best sealer for a carburator gasket is chapstick.  These will allow you to remove in the future if necessary without ruining the gaskets.......If replacing hoses like heater hoses on an engine, (wouldn't apply to 12 horse with no radiator) use just a bit of grease on the nipple before installing the hose.  
Old Age and Treachery will outperform Youth and Inexperence. The thing is, getting older is starting to be painful.

EZ

With in 3 to 5 minutes it starts its additude.
EZ

etat

Something simple to try.  Remove the float bowl on the carb.  Check for trash.  Remove the adjustment jets.  Blow the carb. out with air.  Did you install a new fuel filter.  May be picking up trash or rust from the gas tank.  After it runs a few minutes it could be picking up the trash, or rust causing the motor to sputter and spit, choking it for gas..  After you kill it this trash or rust could be settling back down in the float bowl.  
Old Age and Treachery will outperform Youth and Inexperence. The thing is, getting older is starting to be painful.

EZ

When it starts to miss and back fire it blows black smoke out the muffler. You can smell the raw gas that wasnt burned. I think I'm getting plenty of gas. Thanks.
EZ

VA-Sawyer

EZ, do you have a powered timing light for cars ?  You could put it on the mower and see if the spark is breaking down when it starts to run rough.  If the light starts to flash erratic at the same time the engine starts to act up, then it would indicate an ignition problem.( coil, points, etc.)  If the light is flashing steady then it is probabley a combustion problem. ( pre-ignition, fuel mixture, excess carbon, etc )

VA-Sawyer.

EZ

Will I finally got the old girl running good. The DanG fuel line was almost kink close on the one been coming out of the tank. In other words it wasnt getting enough gas. Thanks for all your answers.
EZ

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