Que:40+ Year Old Briggs&Stratton 4 Stroke

[SteveW]

Guys, (O/T 12" = 1' stuff)

In desperation to sort my garden out I borrowed a "Merry Tiller" rotavator from an old uncle. I recall using it 40+ years ago and now it's well past it's sell-by date but still goes, just. As leaded and LRP petrol is rapidly becoming a memory how will this thing respond to Unleaded (assuming I can breath enough life back into it to go)?

Plan 'B' is to go buy a modern 4hp Honda Engine at circa 190 UKP from Machine Mart.

[Phil Sutton]

Hi Steve,don't forget,you can still buy lead replacement adatives from your local friendly motorists accessory shop,can't give you any brand names off the top of my head,but I thought I saw some a couple of weeks ago,when I was last in buying some oil.
Otherwise,B+S may sell you some new valve seats,machine the old ones out of the cylinder head,and fit the new ones,(interferance press fit I believe)or an engineering firm may be able to do it for you.
A new B+S engine will cost about £200 - £250,our local large Hardware store sells them over the counter.

Phil

[SteveW]

Phil,

Thanks for that. Thinking about it I don't really want to spend any more on the thing than I need to. I may get a new gasgate for the carb but that'll be it. I've been told there is only one garage left selling LRP in town and it looks like the writing is on the wall for LRP anyway.

The engine is well used over 40+ years and I can hear both valves passing pressure so I'm thinking of trying a simple regrind while I save for a new engine. Chances are the rings et al have had it to. Also noticed Machine Mart do 3.5HP B&S for 176UKP but it has a taper shaft not keyed so it'll be a Honda.

It occurs to ask if anyone knows the torque setting to hold the head on these things (3.5HP B&S). The rest of the cultivator is so simple it deserves to live on with a new engine. I may just hang on to the old engine for the usual sentimental reasons but I know I shouldn't.

[Tel]

My experience with B&S engines is that the head torque isn't real critical, as longs as they are down tight and reasonably uniform.

Also, unleaded fuel with the additive will work fine, but DON'T FORGET to add a dash of oil as well, this will prevent that scourge of B&S engines - the stuck exhaust valve. Pulling it up onto the compression stroke when you shut it off helps as well.

[the_viffer]

SteveW

I've got a vertical shaft B&S sitting in my shed. Not too sure how many hp. I think it is 4.

I reckon it is pretty near the vintage you need too. It was given to me by R Clements (A name some of the old stagers will recall.) Oddly enough the board won't display his nickname: it displays it as "thingy". Which is about as useful as a spare thingy at a wedding... He's been dead 2.5years and he gave it to me a good while before then. He got it from some garden machine or other he was breaking up. He said it was sound but i've never run it.

If you want it is yours.

I'm in London.

My job for this evening is to see if I can think of any words so rude that the pc pc which runs this board doesn't know them and so will display them rather than producing a twee translation.

[catgate]

I have had on and off relationships with B&S engines since the time your Merry Tiller was made. They were, at the time your MT was new, a very nasty machine. No bearings anywhere, everything ran in the holes in the aluminium cases. The ignition system was riddled with PMT and the governor system was naff . That having been said, when they were running they did their job. The more recent ones are certainly a much improved thing. I have a 12hp horizontal job on my garden tractor and it is fine. The MT is another matter. When in use they seem to have one of two distinct desires. The first is to race, like hell, in a forwards overland manner, without the slightest interest in digging. The second, if you can get the depth control "anchor" down, is to go vertically downwards. Constantly adjusting this thing up and then down, to give some semblance of a continuous cultivating action, has given many a keen gardener a double hernia and a slipped disc concurrently. The only sensible answer is a machine which is propelled at a constant speed by its wheels with rotary digging blades behind. I manufactured one about 20 years ago and it proved better by far than my old MT. (till the old B&S engine I had used cried "enough"). I now have an aged Howard with a Kohler engine. This is a very different kettle of fish. The engine starts first pull, even after standing under the shed all winter. If you can find one of these engines it will make living with a MT easier.

[SteveW]

All,

Tel, Re Torque: Tight enough was going be aim. Just wondered if there was too much torque figure I could avoid. I have also added 2-stroke oil on the off chance.

The_Viffer: Thanks for the offer but its a Horz shaft and given what Cat has added my Honda option may be the eventual way out.

CatGate: You are clearly not a big fan of the MT and have also put your finger on a number of points I too have discovered both with the MT and most other rotavators used over the years. Even the sexy Honda two/three forward gears and one reverse I've hired bounced around like a bar-steward.

Seems the old MT was a model for nearly every budget rotavator since so there is no real escape from the fix or replace the engine solutions if I want to inherit the thing.

You never know, in another hundred years some ME will be doing a 3" scale version of it ;D

All, thanks for the info.

[catgate]

if I want to inherit the thing

If you are such a masochist I suggest you put your name down for his arthritis, lumbago and bad hip. You will find they complement the MT owners lifestyle very well!!! ;D ;D ;D

[SteveW]

All,

I spent last night doing the valves. The inlet seemed OK but the exhaust seat was well gone. Ended up making an alloy lap to re-face them both. Also needing to take 15 thou off the lengths to get the original tappet gap back. I now have much better compression.

By the way, useful point on the valve spring retention, its difficult to work out how based on just looking at it. It uses a really simple key-hole slot that's a real bitch without the magic tool.

Tonight I tried again and its now a race to get it going before the tank empties out throught that daft carb. Twenty something quid will get me a carb set for a motor that's all but ker-nackered.

Honda here I come.

Thanks for all the help gentlemen, Brigs&Stratton ONE, me Zero. Hoh! dam it!

[SteveW]

Update on my last post:

I checked my posting I thought "what the...!"

If you are confused about the "pregnant dog" I originally used the word that rhymes with "beach".

[the_viffer]

stevew said:

Update on my last post:

I checked my posting I thought "what the...!"

If you are confused about the "pregnant dog" I originally used the word that rhymes with "beach".

It is a funny thing. I thought it'd be amusing to say that it is a pain in the body part the way they change some words. I hoped it would be translated as a pain in the small donkey. I even used the American spelling but what do you know on the preview it rendered it correctly.

Ho hum

[Tel]

viffer said:

SteveW


My job for this evening is to see if I can think of any words so rude that the pc pc which runs this board doesn't know them and so will display them rather than producing a twee translation.

It is said that the late, great journalist-turned-poet Henry Lawson used to amuse himeslf (when he was sober enough) by trying to slip obscure rude words past the editor of the 'Bulletin'. From memory 'merkin' was one such that made it thru'.

[Tel]

.... and for those of you who are wondering ...

www.straightdope.com/classics/a3_232.html

[the_viffer]

As I recall there is a short but magnificent piece in ME in the early 1990s too obscene to reproduce here, or indeed anywhere, concerning firearms for women.

It is not in the series on constructing a replica pistol which was published at about the same time.

[SteveW]

Viffer,

O/T: Do you have the reference to the ME series on the replica pistol series (my other passion)? I even had a letter published in ME the other week on this with support from two other corespondents.

If possible, would you also throw in the other reference.

[Deleted]

If you would like to email me as oldbugger[at]chainganger.co.uk with your email address then I can send you scans, from the B&S Repair Manual, of all the torque, clearances etc data for most of the older series engines.

I would strongly recommend Honda over B&S unless the latter have pulled their fingers out in recent years.

Honda rate their engines using the DIN spec. but B&S use SAE so a 4HP Honda probably has about the same power as 5HP B&S

[the_viffer]

stevew said:

Viffer,

O/T: Do you have the reference to the ME series on the replica pistol series (my other passion)? I even had a letter published in ME the other week on this with support from two other corespondents.

If possible, would you also throw in the other reference.

The ME series was by Ted Pepper in vol 172. I believe Terry is a firearm modeller.

I've sent you a private message (I don't have your email address) outlining the other matter for which I don't have an exact reference to hand

[SteveW]

Guys,

I pushed the boat out today and bought that Honda engine (GX120T) and it's got me thinking about oil.

The blurb says use a detergent oil classified as "SAE 10W/30 SG SF" I've just trawled a couple of sites Castrol/Mobil and nobody makes mention of this (detergent) type other that SAE30 isn't.

The good news is that Castrol suggest their "Performance 10W/40" which has the same spec as my bottle of Halfords "10W/40 API SL CF ACEA A3 B3" for the engine. This is also semi-synthetic.

An interesting point I found was a suggestion to use SAE30 (a non-detergent) oil for running in. Apparently the rings will bed in faster on this stuff, 1,000 miles vice 7,000.

Does anyone know if semi-synthetic is also a detergent oil. How do you tell?

[Phil Sutton]

Hi Steve.
Generaly,diesel engine oil is a detergent oil,and petrol engine oil isn't,although these days they tend to be interchange able,the detergent part being an addative.It was there in diesel engine oil,to hold the soot particles in suspension,old fashioned diesel engines being rather "dirty".The newer varieties burn fuel in a lot cleaner fashion,and thus don't produce so much soot.

Hope this helps

Phil