Id This engine

[doc874]

This is my latest project ( And its woods related it came off a wood splitter ) Fellow at work said it wouldn't't run long and he thought it was electrical. I did a compression test and it came out 110/115 psi. I believe this to be the problem low compression equals poor running. During my endeavors with this the electric starter also quit so i took it apart and found whats in the pics. I want to repair this but need the size of the rings on the piston and of course the fellow don't have any information and there are no serial #'s etc... on the engine. I know its a tecumseh and believe it to be 8hp. Anyone have any ideas what size rings would fit this??

Doc

 

[sawinredneck]

Got a pic of the whole motor? it looks like a tech. but I am not sure. 110-115 on that motor is is AWSOME compresion!! I wouldn't even think about tearing it down!!! Those motors have been know to run down to 30-40 psi! I couldn't tell if the points were burned or not, but the capactor looks older than me! I would check to see if it could be upgraged to the new style ignition, just change out the coil and go. The other thing is these motors are notorious for carb problems. If you have one that runs right, it's one of the best motors you can own. You get one that doesn't want to be set, it can be the worst nightmare you ever had.

 

[PES+]

Tecumseh looks like an HM-80 The numbers are stamped on the top of the fan shroud may be painted over or a tank may be hiding them

 

[Another Bucker]

Hope this works

Up load error?? shoot me your e-mail in a pm and i'll sent you a copy of 3 to 11 hp tecumsec if you need it

 

[PES+]

You will want to get a replacement starter for it....Just curious has this engine even got the fan shroud? You cannot run a fan cooled motor without one. I doubt you need to replace the rings as it would cause you more problems. Have you had it running at all? I am willing to bet it only needs a valve job.

 

[sawinredneck]

You will want to get a replacement starter for it....Just curious has this engine even got the fan shroud? You cannot run a fan cooled motor without one. I doubt you need to replace the rings as it would cause you more problems. Have you had it running at all? I am willing to bet it only needs a valve job.

With 110-115psi compression, it don't need jack inside! This aint a chainsaw!

 

[PES+]

If the valves and seats have worn down there will be not enough clearence and it will only become apparent after running the engine. They can get bad enough to stop after warm up but show good compression when cold.

 

[doc874]

id motor

Yes it has a plastic fan shroud attached to the flywheel. I thought it may be a HM 70 0r 80. I don't have an IPL for this so am unsure of proper compression but, if you say its good than thats ok by me. I am used to chainsaws not these type engines so its a learning curve. I had it running and it ran rough and wouldn't't rev up for long without sputtering out. I changed gas and checked oil etc... The carb seems fine. Could it possibly be the condenser? I would thing its either the condenser or possibly the coil. I looked for the # at the top of the fan housing but no luck. I will get more pics.

Doc

 

[Lakeside53]

Check it doesn't have a low oil switch, and if it does (and if you have enough oil), temporarily bridge it..

..and as the others have pointed out.. 4 stroke compressions are not 2 stroke compressions...

Also, your mixture screw is usully the one on the bottom of the carb bowl.

 

[PES+]

No no..that would be the fan assembly that attaches to the flywheel. There is a metal shroud that covers the whole front of the engine....the numbers are on it

 

[PES+]

There were no...none low oil cut offs on any HMs with points

 

[sawinredneck]

Check it doesn't have a low oil switch, and if it does (and if you have enough oil), temporarily bridge it..

..and as the others have pointed out.. 4 stroke compressions are not 2 stroke compressions...

Also, your mixture screw is usully the one on the bottom of the carb bowl.

That motor should be WAAAAYYYYYto old for the oil pressure switch!!
The screw on the older ones at the bottom of the carb is ussually called the "power valve" The low side is on the carb throat, set it so it idles good, then adjust the "power valve" until it will rev properly. These things SUCK to work on! We used to fight over who had to work on them when they came in the shop, I refuse to work on them now, you can't pay me enough!!

No no..that would be the fan assembly that attaches to the flywheel. There is a metal shroud that covers the whole front of the engine....the numbers are on it

That is correct!!! Make SURE when you call you have all three numbers!! I believe these have type serial and code numbers on them! I know for a fact where I buy my small engine parts the ladies just laugh me out the door if I don't have all three numbers!!!

 

[RED-85-Z51]

aww man I LOVE those old Points Tecumsehs!!!

Im working on an HH70 right now Ive had for a while, great little engines.

Im looking at an HH60 for a Gokart motor..

Gap the points to 0.020 first of all.

Then take the nut out of the bottom of the carb, the one with the needle in it. Clean and blow out all the little holes in it, then clean the bowl, and check for fuel flow.

Now be sure the carb is tight with no air leaks.

IT "should" start with the main jet needle turned out 2 turns from bottomed, the air bleed screw on the side should be out 2-3 turns as well.

Im not a big fan of the old HM series...

Easily recognizable by the intake port being on the left, and the exhaust port on thr right.

I like the H, HH, OH and OHH series engines..

 

[doc874]

Ol tecumseh

This one isn't mine and i am regretting agreeing to work on this thing, but its for one of my RCMP friends so i couldn't' say no. He also gave me a old chainsaw ( Pioneer- boat anchor. And has a rebuilt 4hp snowblower for me as well. ) Its a favor. Here are some more pics. I now have a book, compliments of Charles here and its a great help. As you all can see the breather is one of those on the side and i haven't taken it apart yet, this could be the problem all along. The thing will run at low speed but sputters and dies when i increase the fuel supply, so maybe ( fingers crossed ) that its a plugged air filter/screen. "No air, No-Run good". Anyway its been fun. Thanks for the input.

Doc

 

[Sprig]

aww man I LOVE those old Points Tecumsehs!!!

Im working on an HH70 right now Ive had for a while, great little engines.

Im looking at an HH60 for a Gokart motor..

Gap the points to 0.020 first of all.

Then take the nut out of the bottom of the carb, the one with the needle in it. Clean and blow out all the little holes in it, then clean the bowl, and check for fuel flow.

Now be sure the carb is tight with no air leaks.

IT "should" start with the main jet needle turned out 2 turns from bottomed, the air bleed screw on the side should be out 2-3 turns as well.

Im not a big fan of the old HM series...

Easily recognizable by the intake port being on the left, and the exhaust port on thr right.

I like the H, HH, OH and OHH series engines..

Just curious why you say gap to 0.02? I'm currently trying to get a friends OHV 5.5 Tecumseh gen set up and running and ran into this guide for gaping gas engines, according to this all the Tecumseh engines are gapped at 0.03, so is there a reason to make it smaller? Just wondering, the link is here and lists many types of engines, page 4 is where I was lookin' > http://72.14.253.104/search?q=cache...eh+5.5+sparkplug+gap&hl=en&ct=clnk&cd=8&gl=ca

And no, I haven't got this thing running yet Have replaced fuel line (a biatch of a job) and the ring gasket for the float bowl, have spark..... and a really sore elbow after 100 pulls.....GAH!

 

[doc874]

Just curious why you say gap to 0.02? I'm currently trying to get a friends OHV 5.5 Tecumseh gen set up and running and ran into this guide for gaping gas engines, according to this all the Tecumseh engines are gapped at 0.03, so is there a reason to make it smaller? Just wondering, the link is here and lists many types of engines, page 4 is where I was lookin' > http://72.14.253.104/search?q=cache...eh+5.5+sparkplug+gap&hl=en&ct=clnk&cd=8&gl=ca

And no, I haven't got this thing running yet Have replaced fuel line (a biatch of a job) and the ring gasket for the float bowl, have spark..... and a really sore elbow after 100 pulls.....GAH!

Yours certainly sounds like fuel problems. Does yours have the intake and exhaust valves as well? I'm starting to think this could be my problem, the valves look good when i pulled the filter, abit of carbon on the exhaust valve but i expected that. I will measure the gap later. I may pull the front cover and look at the valve stems/seat from that angle as well where they contact the cams. Before i do this i may as well buy a new condenser and coil first before going to all that trouble. Do the easier things first. Good luck with yours.


Doc

 

[Sprig]

Yours certainly sounds like fuel problems. Does yours have the intake and exhaust valves as well? I'm starting to think this could be my problem, the valves look good when i pulled the filter, abit of carbon on the exhaust valve but i expected that. I will measure the gap later. I may pull the front cover and look at the valve stems/seat from that angle as well where they contact the cams. Before i do this i may as well buy a new condenser and coil first before going to all that trouble. Do the easier things first. Good luck with yours.


Doc

I'm inclined to think so too as I have no idea how dry it was run (and it ran fine, 2 years ago, (DOH), so it is probably gummed up pin-holes in the (very simple) carb, I am loathe to take this apart any further though, but the carb is about as simple as they get. If I do depart it from the body i will soak it in gas for several days first before I get into the guts of it (I really don want to do this as it is a freebie job for a good mate. From what I understand this gen has less than 6hrs on it A typical example of improper storage, then a year down the road peeps expect it to just fire up!!!!!!!!!!! GAH and double GAH!!!! :censored:

:greenchainsaw:

 

[RED-85-Z51]

Just curious why you say gap to 0.02? I'm currently trying to get a friends OHV 5.5 Tecumseh gen set up and running and ran into this guide for gaping gas engines, according to this all the Tecumseh engines are gapped at 0.03, so is there a reason to make it smaller? Just wondering, the link is here and lists many types of engines, page 4 is where I was lookin' > http://72.14.253.104/search?q=cache...eh+5.5+sparkplug+gap&hl=en&ct=clnk&cd=8&gl=ca

And no, I haven't got this thing running yet Have replaced fuel line (a biatch of a job) and the ring gasket for the float bowl, have spark..... and a really sore elbow after 100 pulls.....GAH!

On EVERY points Tecumseh Ive EVER worked on, from a little 85cc 2 Stroke on a Weedeater, to a big old Iron model, the points covers all had "gap points to 0.020" on them somewhere.

I just went out to my HH70, pulled the flywheel, gapped the points to 0.030, put it all together and had no spark, put it back to 0,020, and had a snappy blue spark. These things are touchy on points.

Now for setting the air gap on the breakerless coil, rule of thumb is 1 business cards thickness.

OHV5.5, thats an Enduro engine, correct?
Whats the trouble with it, thats the same engine as the Tecumseh Power Sports engines I work on so much, except the PS engines have plastic cams.

 

[RED-85-Z51]

Yours certainly sounds like fuel problems. Does yours have the intake and exhaust valves as well? I'm starting to think this could be my problem, the valves look good when i pulled the filter, abit of carbon on the exhaust valve but i expected that. I will measure the gap later. I may pull the front cover and look at the valve stems/seat from that angle as well where they contact the cams. Before i do this i may as well buy a new condenser and coil first before going to all that trouble. Do the easier things first. Good luck with yours.


Doc

What filter did you pull to see valves?

Here is what you do to check valve lash.

Remvoe the valve cover, just under the int and exh. ports. Turn the piston so it is TDC on the compression stroke. Generally speaking, no more than 0.010 gap and no less than 0.003 on either valve.

You wont find the valve stems inside the case, they are under the breather where you checked th valve lash. Only things in the case are:

Governor gear
Crank
Rod
Piston/rings
Cam
Tappets.

On your L-Head engine the valve lash is adjusted closer by cutting the valve seats, and opened up by grinding the end of the valve stem.

OPn Sprigs OHV engine, he has a large valve cover on top of the engine, he measures valve lash on top of the engine by doing the TDC thing, but he measures between the Valve stem and Rocker arm.

If your valve lash were out, you would have either no compression, or an extreme difficulty pulling the rope.

 

[RED-85-Z51]

I'm inclined to think so too as I have no idea how dry it was run (and it ran fine, 2 years ago, (DOH), so it is probably gummed up pin-holes in the (very simple) carb, I am loathe to take this apart any further though, but the carb is about as simple as they get. If I do depart it from the body i will soak it in gas for several days first before I get into the guts of it (I really don want to do this as it is a freebie job for a good mate. From what I understand this gen has less than 6hrs on it A typical example of improper storage, then a year down the road peeps expect it to just fire up!!!!!!!!!!! GAH and double GAH!!!! :censored:

:greenchainsaw:

Dont bother soaking it..

Take the nut that holds the Carb bowl on, OFF. You will see a thru hole in the bottom of the threads, then 1 hole that goes down the center to the bottom of the nut, and if you look closely at the very TOP of the threads, you will notice a teeny tiny little hole, it goes DOWN, at about a 45* angle.

All these holes must be totally free of debris.

With the bowl off, check for fuel flow.

Button is all back up and give her a good prime and let her rip. No small orifices in the carb iself, other than the Bowl vent..and the Air bleed. But we'll worry about them later if we have to.