Briggs and Stratton engine

[8ob]

Thanks for the replies, as I've said before I have a new Honda rotavator so a costly repair or new motor

is out of the question. I can get piston rings quite cheaply and that is about as much as I'm going to spend but the question remains what should the compression be after rings and piston rebuild. I am not going to buy a new motor or throw good money at a second hand one, been there and done that and landed up forever spending on them so a cheap repair for a spare is all I want to do. Thanks once again for all replies. Pud.

I wouldn't worry about what the compression test should read after fitting a new piston and rings, providing the bore is in good shape it will be right. I think you are being thrown by wet bore compression readings,a knackered piston in a bore can still give a high reading if there is enough oil up the bore,doesn't make it right.

Bob

 

[GRW]

B&S did (20 yrs ago anyway) do different build specs of an outwardly similar motor - so the basic one was a "500-Hr" life engine with just an alloy bore and unhardened valves and valve seats. One of those problems wouldn't so well being nipped up.
Industrial Plus model had steel liner and stellite valves.
Best one was the Vanguard model (cos it was a badged motor made by I think Mitsubishi or one of the Japanese Mfrs, and not B&S.

The smoke might be cos cooking the motor also barbequed whatever passes for valves stem oil seals in the dinky aircooled head?

If you don't want to spend on parts you could just try cleaning up the piston and bore, unsticking any rings by removing any alloy smears and cleaning up the ring grooves and refitting, and checking that the excessive heat hasn't burnt out the exhaust valve seat etc.

 

[Edward Teach]

Also known as PIECE OF SH1T

Steady on,
You'll hurt someone's feelings

 

[Ruffian]

If seized up, then what about the big end failing again?

Would pull the head and barrel to have a looking and possible hone to try and salvage the top end.
But would be tempted to see if any lawnmowers or similar run the "same" engine components as a donor.

 

[slim_boy_fat]

it's either a cheap repair or nothing.

Or....tolerate the smoke, run it as is until.....

 

[vmaximus]

This motor is from 1996 so I am not too concerned about it. I have best part a full blown motor from 1988 the rings have the same serial No so I'm assuming most other parts are. As I've said it's still running and performing ok other than a bit of smoke so when I get my new m/c back I will whip the head off and have a look, if it's ok I will replace the rings, I have a spare piston and head so it's not a big job to replace them. By the way I forgot to mention that this M/c had been stood in a field for about 4 1/2 years before I got it. I replaced valves and springs but there could have been some previous wear and tear anyway. If I do go ahead and change the rings and piston what do I need the new ring gap to be. Pud.

 

[johnny7]

Hi

I bought this 3.5hp Lawn king from free ads for just £20, I got it home and couldn't resist trying it out but around three quarters of the way through it stopped dead and wouldn't pull over again!

Same thing- There was no oil in the sump!, I gave it 30mins to cool off then filled it with oil and gave it a yank and it turned over!, Another pull saw it fire up with a puff of blue smoke which cleared immediately after it started!, It's been this way ever since, It happened at least five years ago and it still runs fine (Allbeit with a single puff of blue smoke!) I do run it dry of fuel on the last useage of the year and cover it up well through winter!

John

 

[tom2207]

Also known as PIECE OF SH1T

Ive a few of their industrial grade engines and they are grand , not very refined and the carbs just throw petrol down their throat but overall Ive had great service out of them , they arent Honda , but then again new Hondas are not old Hondas anyhow.

 

[vmaximus]

But what do I need to gap the new rings at. Thou or metric.

 

[OJCar]

As a guide, Ring gap of 0.004inch per inch of bore size for an ordinary Normally Aspirated Four Stoke engine.

So, if 3inch bore then ring gap is 0.012inch

 

[tom2207]

from 3 to 10 thou is the guide from memory ,,,, Im happy as long as there is a gap its not F1 after all.

Project farm over on you tube uses wee mowers to test all sorts of things and they do take some severe beatings before finally giving in ,,,

 

[Pete.]

But what do I need to gap the new rings at. Thou or metric.

Definily don't gap them in metric it's got to be thous

Hondas have metric gaps.

 

[vmaximus]

@pete, is that the same as not using a metric adjustable spanner on a imperial nut or a imperial adjustable spanner on a metric nut. Anyhow after that crappy tongue in cheek reply to pete thanks for the all the info regarding this slight malfunction and ring gap size. Once again a big thank you to all. Pud.

 

[gaz1]

Hi

I bought this 3.5hp Lawn king from free ads for just £20, I got it home and couldn't resist trying it out but around three quarters of the way through it stopped dead and wouldn't pull over again!

Same thing- There was no oil in the sump!, I gave it 30mins to cool off then filled it with oil and gave it a yank and it turned over!, Another pull saw it fire up with a puff of blue smoke which cleared immediately after it started!, It's been this way ever since, It happened at least five years ago and it still runs fine (Allbeit with a single puff of blue smoke!) I do run it dry of fuel on the last useage of the year and cover it up well through winter!

John

i have one of those and there really easy to change there diaphram and get going again

i also have one of these as well


that wont start without oil in it

thats on my merry tiller cultivator and dont i know it

 

[Alan Reynolds]

@pete, is that the same as not using a metric adjustable spanner on a imperial nut or a imperial adjustable spanner on a metric nut. Anyhow after that crappy tongue in cheek reply to pete thanks for the all the info regarding this slight malfunction and ring gap size. Once again a big thank you to all. Pud.

You mean you haven’t got one of These!

 

[vmaximus]

I haven't got one of those spanners but now I've seen one i'm sure it would make things a lot easier working with AF and Metric without lugging two different tool boxes around, 1 spanner fits all brilliant!. Pud.

 

[Ruffian]

Just on Facebook.
6.5hp briggs engine
£85.