2.5 Tecumseh Rebuild Questions

125ccCrazy

Well-Known Member
#2
I am rebuilding a 1964 H25 2.5hp Tecumseh. I am putting new rings, seals,gaskets,spark plug,and carb kit. Should I mess with the points? Should I lap my valves? If so what is the best way to do so?

has anyone used amsoil or should I use regular 30 weight?

like this stuff
Amazon.com: AMSOIL Synthetic 4-Stroke Small Engine Oil 10W-30/SAE 30 #ASE-QT: Automotive
I take an old set of lifters and glue them to the top of the valves using 2 part epoxy...make sure both valve and lifters are clean prior to gluing.. I then let them set overnight to cure... oil the valve stems, chuck the lifter in a cordless drill and using some valve grinding compound I grind the valves until I get a nice grey seat on both valve and seat...

I would inspect the points, if they are rusty, pitted then replace them and set the gap... Check the points cam as well and make sure it's not flattened...

I would not use synthetic to break the engine in...

Be sure to hone the cylinder before ringing it and definately grind the valves..
 
#3
Thanks! If i don't have any old lifters should I get one of those suction cup things? Is there a certain grit of grinding compound that I should use or are they all the same?

I will be sure to pick up a hone for the cylinder. The cylinder seems to be in great shape, can I just pick one of those brake cylinder hones up and do it my self or should I take it to a shop?

What is a good break in oil? What kind of oil is best to run after break in?

Sorry for all of the questions this is my first small engine rebuild.
 

125ccCrazy

Well-Known Member
#4
Thanks! If i don't have any old lifters should I get one of those suction cup things? Is there a certain grit of grinding compound that I should use or are they all the same?

I will be sure to pick up a hone for the cylinder. The cylinder seems to be in great shape, can I just pick one of those brake cylinder hones up and do it my self or should I take it to a shop?

What is a good break in oil? What kind of oil is best to run after break in?

Sorry for all of the questions this is my first small engine rebuild.
There are two grits for valve grinding compound, Fine and Coarse.... Start with the coarse until you get an even grey line on both surfaces follwed with the fine.... I don't care for the suction cup tools myself, they will work but it takes alot longer doing it by hand especially if there is any pitting in the seats..

I prefer ball hones, straight hones like a brake hone don't always get the whole surface... You can find pretty good deals on those on ebay.. Measure the bore and get a hone thats about 1/4" larger in diameter.... If it measures 2 1/4 get a 2 1/2".... If you search the net a little there should be info on honing that might help you.... I use the ball hones, a cordless drill and wd40 for lubricant.... On the alum bores you dont want to go crazy with the hone, just enough to deglaze it and get a cross hatch pattern..

Standard SAE 30 will be fine for break in... after break in synthetic will be work....
 
#5
I borrowed a motor cycle hone from a friend that I hope will work. It compresses down to as small as 1-3/4” and has 4” long stones. I will attach a picture of one like it…this should work right?

If I don’t have any old valves would it work to cut a piece of dowel and glue it to the valve to hook to my drill for lapping?

The valve grinding compound that I bought was all that was on the shelf and is Permatex 34A. There wasn’t another kind or grit, will this work?
 
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