Rough H25

[jackeo21]

Hey all,

Did a deal at a swapmeet recently. $5, I scored this old beast for :laugh:

This is an old H25 Tecumseh. I know this because the intake manifold is very small on the inside. It didn't come with a shroud so I'm not sure what year it is. Maybe someone can tell me by looking at it?? It's probably an Australian kirby Tecumseh, same thing just different build location.

This is a Cast iron bore, ball bearing crank motor! This has gotta be a rare sight, no?

This old motor has probably been sitting for many more years than I have even been alive :doah:

All the internals are in good condition, the piston almost new! All it needs is a shroud and a carb.

Now, can anyone tell me what carb I need? The inlet is a really neat 2 piece setup. I know the bolt pattern will be the same as an H35 carb. I'd like to get away with a cheapo china carb, because it's cheap. I read about them and I know there's a chance you can get a lemon :laugh:

Plus, what piston rings do I need? The original top ring seized into the piston so it just split upon removal. Hope I can get some from MFG supply as they ship to NZ.

Oh, me and a few friends were kicking around the idea of small single seat inboard type boats, and I thought this engine would be a perfect candidate.

This engine is in desperate need!

 

[JohnnyTillotson]

Is the magneto in there? Looks empty under the flywheel. Dont you need valves too? Or are they just removed? Also measure the bore diameter. If i remember correctly the 2.5 and 3.0 are the same. I think the stroke is different. Some carb numbers to search for are 29636, 29343, 26939, 30049, 630965, 630949, 630882, 630912, 630894

 

[jackeo21]

I have all internals (inc. valves), and the magneto was stuck to the flywheel magnets when I got it! I'll measure the bore soon.

 

[KustomKartKid]

The cast iron bore is common in the H25...the roller crank bearings are unique though I think.

 

[markus]

Thats a really interesting setup, Its got the flyweight easy start cam. and has the oil pump provision style sidecover. I have had one of the sidecovers in the past but I cant remember what the heck it was on. I could not figure out what all the funky extra castings were for until someone recently posted up the insides of an early engine that actually had the oil pump system in it and it all made sense.

hard to say what year it is, For the US though they dropped the aluminum flywheel in the 74/75 timeline in the small frames.

The intake size is irrelevant, depending on app even the 3.5's would have a small intake , so for ordering parts you really need to do some thorough measuring of the bore and stroke.

 

[Not so mini bike]

Thats a really interesting setup, Its got the flyweight easy start cam. and has the oil pump provision style sidecover. I have had one of the sidecovers in the past but I cant remember what the heck it was on. I could not figure out what all the funky extra castings were for until someone recently posted up the insides of an early engine that actually had the oil pump system in it and it all made sense.

hard to say what year it is, For the US though they dropped the aluminum flywheel in the 74/75 timeline in the small frames.

The intake size is irrelevant, depending on app even the 3.5's would have a small intake , so for ordering parts you really need to do some thorough measuring of the bore and stroke.

The outside of my side cover looks different Markus.

 

[Not so mini bike]

This is mine.

 

[markus]

His is a later casting heres the inside:

yours is early.....like pre 62, Look at the engine Honky just sold

 

[Not so mini bike]

His is a later casting heres the inside:

yours is early.....like pre 62, Look at the engine Honky just sold

Well would ya look at that. You know I had that engine in my hands on Sunday and didn't even notice that.

 

[Dr. Shop Teacher]

Welcome to the "dark side," young man! I do like the Tecumsehs even though they can frustrate you no end. Keep in touch with Markus, he knows his stuff--helped me a lot recently on my H35.

 

[jackeo21]

Thanks for the info people. I did a rough measurement of both the bore and piston and it was about 2.3 inch diameter. So that could be either a 2.5hp or 3.0hp by my knowledge

I posted a wanted ad in the wanted section for a few parts I need, which would be a shroud/shroud bracket/governor linkages and a coil :thumbsup:


I'll get a few more pics up of where I'm at soon. Looks like timing the coil is gonna be fun :hammer:

At least I got the chunks of exhaust elbow out of the port. Now I just have to get out all the snapped bolts!

 

[jackeo21]

Well I managed to buy another H25, this one from a friend. I had it running a few weeks ago. It's an aluminium bore 70s model. I was going to raid all the parts that I need from it. I think it would be worthwile taking all the parts from an aluminium bore plain seal engine and putting them into a ball bearing cast iron bore motor

Should I use the running motor or use my $5 motor? Your opinion is appreciated! I will have to compare part conditions. Nothing will be scrapped. I just hate to part a running engine :surrender:

 

[Dr. Shop Teacher]

Well I managed to buy another H25, this one from a friend. I had it running a few weeks ago. It's an aluminium bore 70s model. I was going to raid all the parts that I need from it. I think it would be worthwile taking all the parts from an aluminium bore plain seal engine and putting them into a ball bearing cast iron bore motor

Should I use the running motor or use my $5 motor? Your opinion is appreciated! I will have to compare part conditions. Nothing will be scrapped. I just hate to part a running engine :surrender:

I'd see what fits and play with the older engine...that looks like a very cool project to do! Merry Christmas...as I believe you are nearing the 25th!

 

[KustomKartKid]

If it ain't broke don't fix it. That saying holds true no matter what country you're from but especially true if your someplace where parts and engines are not readily available. If that aluminum bore motor isn't smoking and has good pop to it, bolt it in and run it. In the meantime you can scrounge around for the parts you need for that steel bore motor and mess with it in your spare time. Somebody on here might even have what you need for free or cheap.

 

[jackeo21]

I will leave the H25 under the bench until parts for it are found :thumbsup:

The motor I picked up is a really clean 1971 H25. I'll make a thread for it. It's actually a steel bore motor, which was a nice suprise! It will get a carbon clean, block clean, light sand, paint (white), air filter,spark plug and an oil change.

 

[jackeo21]

I'd see what fits and play with the older engine...that looks like a very cool project to do! Merry Christmas...as I believe you are nearing the 25th!

Merry Christmas to you too Doc! I understand it's Christmas day for you today.

 

[jackeo21]

Coming Along...!

It's update time!

Yes I'm aware of the thread bump, but I thought i'd update this little engine here instead of creating yet another thread about it!

As you can see, this little tec has come a long long way from the time I got it! And there's not much more I need to do to her before shes all up and running again!

Yesterday, my set of brand new piston rings arrived and i'm more than happy with them. I purchased a set of NOS rings as advised by multiple members. If nybody is looking for a standard ring set for the H25 or H30 with the 2 5/16" bore, the part number is 27565 (thanks 1stBxMopar!). I managed to pick up my genuine NOS set for under $10.

My minibike correct throttle linkage also arrived and i'm happy with it :thumbsup:

Now all that is left to do is to weld up the Shroud, get the timing right (somehow), purchase an inlet manifold and rebuild the original carburetor. Really not far away from getting her going again! I feel like this engine is special in the fact that most people would have given up on it a long time ago, as it was heavily corroded, had many snapped off bolts, was missing parts, etc... especially way down here in New Zealand where parts for Tecumseh engines are very hard to find and not to mention expensive, so I made it my mission to save this little H25.

But looking at where it is now i'm very happy with my work :thumbsup: It certainly is the most challenging engine I have ever worked with as it is not only different than my usual Briggs and Strattons but required much more work, time and effort to restore. I'm just hoping it'll run right!

Also, I was trying to be sneaky and use a Briggs oil seal on the rear but upon test fitting it I found that its inner diameter was too large :laugh: so i'll have to go hunting for the correct Tecumseh seal.

I think this will be a better little motor for my minibike than the 3HP Briggs that I built during the build-off. I like the bowl carbs on these little tecs, I think they work better than the pulsa-jet briggs design. The cast iron sleeve and ball bearing crankshaft are also very appealing!

I will get some more pictures of it tomorrow in it's half assembled state.

Thanks,
Jack

Here is a little before and after!

 

[neo71665]

Updates of your own thread don't count as thread necro-ing.

That thing cleaned up pretty good, I know you have your share of headaches and busted knuckles in it.

 

[jackeo21]

Here are some more photos of the engine :thumbsup: