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Collection, Preservation and Display of Old Lawn Mowers

Tecumseh Aspera running issues

Hello all. I have come back to the club to ask if anyone could help. I had quite a long string on another post regarding the same machine but this is not totally related to that.

My issue is I have still got a mower which has a Tecumseh/ Aspera engine, built as I have been advised before 1970 and I spent a while stripping and re building it a few years ago.

I have not had reason to use it much, though when I do, it seems to be to cut rough and sometimes tall grass and brush, which may not be the best use of such a machine with an old engine.

I have found, when I have used it, that it takes a lot of starting (I have to admit that the recoil starter is missing as it broke and I could not fix it so I start it with a drill and socket driving the retaining bolt on the top of the drive shaft), but once started it runs seemingly OK but only when the throttle is left mid range on the control. If you push the said control as far forward as it will go the revs don't drop (the kill switch connection is disconnected as it won't run at all with it attached to the spade it should slide onto). If, however, you try and pull the throttle control back, beyond the mid range as described it starts to rev really quickly and there seems to be no regulation of it's revs at all. If you push the throttle slightly forward again the revs drop and it runs as before. Now, when I did the re build I did fit a new carb, Delorto, but I have no idea if I set ip up correctly. When I stripped the internals of the crank/ drive down, I have no idea if I set the governor up correctly, I think I have noticed the outer governor arm does not seem to be pulling on the spring but, because it's behind the cowling, it can't be viewed when in normal use.

I'd appreciate some pointers to see if I can get this running better, if possible. I would also be interested if it would be worth offering this machine to someone who could give it not only a more educated ifx up but a new home as I will not have storage for the long term soon.

Thanks for your time and I hope to hear from someone.

John Morris.

P.S. if you want to see it running, use this link to see on Youtube.


hortimech Mon, 05/04/2021

Interesting machine, Mountfield M4 fitted with an Aspera LAV30 or 35, probably mid 70s, the airshroud appears to be from an Atco rotary, whether the main part of the engine is from the Atco should be easy to tell, does it have a tapered crank extension or is it a straight 7/8 diameter crank ?

DJD Mon, 05/04/2021

Yes the shroud as fitted would use a totally different plastic type air filter body, with a longish square in section foam filter.

There are adjusting screws on these carbs. and their linkages and regulator shaft etc.

After a while the very hard socket will be chewing the nut up that hods the flywheel on.

I like old Mountfields and have plenty of new springs, pawls etc, where abouts are you?

wristpin Mon, 05/04/2021

KDefinitely from an Atco four wheel rotary ot their roller rotary and the air cleaner is right for that era.

wristpin Tue, 06/04/2021

Definitely not off an Atco roller rotary mower, they had black engines

Not the one that I'm thinking of. Green engine and handle bar mounted tank and cream deck. 

wristpin Tue, 06/04/2021

You are thinking of the 18 & 21 inch four wheeled Atco rotary mower.

Yes, that's the engine that the OP posted on a Mountfield chassis, is it not? 

hortimech Tue, 06/04/2021

Well the airshroud and carb appear to be (if from different era's), but you said 'roller' and the 18 inch Atco roller rotary mower (painted red and white) had basically the same engine as the cream painted push 4 wheel Atco rotary mower, but it was painted black.

All in all, it is a 'Bitsa'

Johnone Wed, 07/04/2021

Hello DJD. I am in Sheffield. The engine is an Aspera from the late 1960's so I've been advised before. It has a Tecumseh Indian logo on the front of the housing. The mower was left buy a guy who used to rent my mother in laws garden for a while. Where he got it from I have no idea. It just turned up, he used it to keep the grass down, then he moved to Scotland and left the mower behind. The blade setup is also interesting. It has the carrier arm and a triangular blade on each end, bolted on. The hub, that the blade carrier arm is bolted to comes off by hitting it with a hammer, not using bearing pullers. I had to put a new carb on as the old one was not in good condition and the emulsion tube was in poor shape. I tried to replace the tube but it made things worse so I got a new carb. The linkage, which is quite different from most Tecumseh setups I've seen was damaged and I tried to make some replacements but I don't know if I did it like for like or not. I do know the engine used to hunt at low revs, now, as I advised in the original post, it does not drop to low revs at all. If you watched the video via the link I posted, that is about all it ruins at most of the time. If you try and throttle up, it revs really high so I don't throttle up. I would love to give this to someone who can set it up to run correctly as I am not trained and don't really have the time to tinker as I was able to a few years ago. Anyway. Sheffield is where I am. Any good? Thanks.

Johnone Wed, 07/04/2021

Hello Hortimech. Yes, definitely a bitsa. It was left by someone who used to rent my mother in laws garden. He moved to Scotland and left the mower behind. The Mountfield body is just in 4 wheels, no roller. It has an angled mulch spout at the back which throws the grass away to one side. The engine is definately a Tecumseh derived Aspera, built in Italy I believe. The carb was purchased by myself (Delorto) and fitted. I had to reverse the link arm on the top as it was back to front to what was needed on this machine. If you looked at the video I sent the link to, that is about all the speed it will safely run at. If you throttle up, from that position (control lever at mid position on the slider), the engine revs really fast and would damage the engine so I don't throttle up. I wish I knew what to do to make it run better, I am not sure, as I advised in the original post, if I have it set up as the governor arm does not seem to have any tension or pull on the spring. I do know it used to hunt at low revs but always picked up to run when you throttled up so I guess it may have run better before I tinkered with it.

Anyway, it's good to have the conversation. Any help or advice to help would be a great help.


Johnone Wed, 07/04/2021

Hello again. To answer the crank question. When I took it apart, it has a straight crank shaft, from memory. it is an Aspera engine based on a Tecumseh engine from the 1960's. There is a Tecumseh red Indian logo on the front of the housing, and the cutting system underneath is an Atco, 2 blade (triangular) set up but the hub on the shaft comes off by hitting it with a lump hammer, not by pulling it off with bearing pullers (tried that and it almost destroyed my bearing puller). So an old engine, made up of different bits from other machiens but definately a Tecumseh based power unit.

hortimech Wed, 07/04/2021

Ah, the old, lay the cutter boss on something solid and hit it hard, trick. Been there, done that, often. If that is the set up, then it will have a tapered crankshaft extension, If the airshroud is original (to the engine) then the engine is from the mid 70s - early 80s. The problem is that the airfilter assembly is from an earlier engine, just how much earlier could be confirmed by photos of the governor linkage under that cover over the carb and manifold.

DJD Thu, 08/04/2021

Sorry, it's about a hundred miles too many away for me, I live in Northants. Thanks for the offer. I found a Princess machine with the same black engine cowling only today at a local recycle, a pity it was a plastic deck and badly broken about.

hortimech Thu, 08/04/2021

I fail to see how you could find a 'Princess' with any colour of engine cowling, they were electric powered.


Adrian Thu, 08/04/2021

DJD - if Mountfields are your thing I may have one available soon (the neighbour has been moved by the swearing heard through the fence to offer me a mower - if she can find one that will start herself!) - it's got a new blade to go with it that must at least quadruple the value, and I'm in Oxon.

Email me for further details...

Johnone Thu, 08/04/2021

Hello Hortimech. I could take some images of the linkage you wrote about but I have a folder full of paperwork which I acquired and the linkage in question is described as a 1966/67 version so that part of the engine, at least, is very old. I don't know when, or if the cover over the block etc had been changed to a newer one or from a different engine make but it's all there has ever been on the engine since it was left as I described in an earlier post. If you want, I could scan the page and attach it to this string?

hortimech Thu, 08/04/2021

Just take the cover off the carb and take a picture of the linkage, I can tell from that how old the intake side is. The airshroud is definitely older than the airfilter, but without dismantling and measuring the bore and stroke, there is no way of knowing whether it is an LAV30 or 35, the earlier versions of the Atco rotary (ignoring the even earlier versions fitted with a Villiers lightweight, or the even earlier versions with the two stroke Villiers engine) had the LAV30, later versions (early 70s) used the LAV35. Due to the fact that I rebuilt some many of those engines early on in my career, I could probably strip and rebuild one in my sleep.

DJD Thu, 08/04/2021

Hortimech, sorry if I used the wrong model name, it was the first that came to mind, I could find no model designation on it. Not a marquis or M model either though.

Johnone Sun, 11/04/2021

Hello again.

Please find attached a couple of schematics of the exact type of linkage I have on the mower and a couple of images as well. The one with the pull starter fitted is just to show that I had tried to get a new one but it needs a new cup and cage to work as the new pull starter has a smaller diameter mechanism housing so the pawls don't reach to the current cup I/D and engage with the teeth on it. I got a new cup as well (Think its still in one of my tool boxes but I could not seem to find the cage so didn't complete the job.

Anyway, take a look at the attached and see what you think.

wristpin Sun, 11/04/2021

I remember the larger diameter cup being an alloy casting and the matching retainer ( cage?) having a little tension spring inside to assist with pawl withdrawal . Used on both Aspera and Tecumseh branded engines, I think.