Valve seat issue Briggs & Stratton

BlueEA · 05-02-2021, 09:40 PM

Hi everyone,
I'm not sure if this thread is in the right section & if not by all means move it.

I have a lawn mower that decided it didn't want to play anymore and just stopped suddenly & wouldn't start again. After going through the normal procedure of process & elimination to no avail I did what I should have done initially, a compression test, as I didn't feel that it was a fuel or electrical issue as it was just too sudden a stop. The result was zero compression. So after removing the cylinder head I found what I suspected that the intake valve seat had dislodged.

Given that I've been & spoken to a number of mower repair places I'm starting to feel I'm missing something here as I couldn't get a definitive solution to stop this happening again.

So I Googled it only to find that the popular solution was to use a broad point punch and not aggressively just carefully punch small indentations in the block around the perimeter of the valve seat about 5mm from the edge. When the motor/block heats up & being alloy it expands these indentations causing extra retaining pressure around the valve seat limiting the likely hood of it popping out again. That's the theory anyway.
So what happens when the block is cold what's to stop it from popping out?? Furthermore I just don't like the idea of punching indentations in the block. Does anyone know of a better alternative or solution?

Sorry about the long thread.
Cheers
Grahame.

hayseed · 05-02-2021, 10:35 PM

Quote:

Originally Posted by BlueEA

I just don't like the idea of punching indentations in the block. Does anyone know of a better alternative or solution?

.

Besides getting another Motor..?? No..

I'm probably not the best person to reply to your Question, though..

As far as I'm concerned Anything Briggs & ****ten is just throwaway Rubbish..!!! SORRY..

**aussiblue** · 05-02-2021, 10:57 PM

Like this; https://www.youtube.com/watch?v=6JL2tyNqBJ4 ? And yes it's also what the Briggs and Stratton Factory Workshop manuals says to do.

Franco Cozzo · 05-02-2021, 11:14 PM

I'll let you in on a trade secret, I also encountered the problem of no compression on my mower.

This is how I fixed valve seat issues on my Briggs & Stratton lawn mower.

1) Throw out old lawn mower
2) Buy $179 lawn mower on special at Aldi

**aussiblue** · 05-02-2021, 11:31 PM

Here's a copy of the page from the Briggs and Stratton Factory Workshop Manual. And if think that is crude, they also use a special knurling tool to knurl a pattern on worn cylinder walls to reduce their internal diameter. You need a different mind set when dealing with these cheap motors compared to car engines etc, They always were cheap and relatively disposable even made in the USA now being made in China they are even cheaper and more disposable. So yes usually it's cheaper and more sensible to buy a new mower than buy any parts costing more than a few dollars. But I know where you are coming from and I have to admit I keep repairing old mowers that I never use just for the fun of it. I use a Ryobi rechargeable one these days; lighter and much quieter and more reliable. In fact it's so light and easy to use the missus does the mowing for me now.

**Silver Ghia** · 05-02-2021, 11:38 PM

Quote:

Originally Posted by BlueEA

Hi everyone,
I'm not sure if this thread is in the right section & if not by all means move it.

I have a lawn mower that decided it didn't want to play anymore and just stopped suddenly & wouldn't start again. After going through the normal procedure of process & elimination to no avail I did what I should have done initially, a compression test, as I didn't feel that it was a fuel or electrical issue as it was just too sudden a stop. The result was zero compression. So after removing the cylinder head I found what I suspected that the intake valve seat had dislodged.

Given that I've been & spoken to a number of mower repair places I'm starting to feel I'm missing something here as I couldn't get a definitive solution to stop this happening again.

So I Googled it only to find that the popular solution was to use a broad point punch and not aggressively just carefully punch small indentations in the block around the perimeter of the valve seat about 5mm from the edge. When the motor/block heats up & being alloy it expands these indentations causing extra retaining pressure around the valve seat limiting the likely hood of it popping out again. That's the theory anyway.
So what happens when the block is cold what's to stop it from popping out?? Furthermore I just don't like the idea of punching indentations in the block. Does anyone know of a better alternative or solution?

Sorry about the long thread.
Cheers
Grahame.

I would have thought the idea of the indentations around the perimeter would be to physically lock the valve seat in its position regardless of whether its hot or cold.

And its amazing what info aussiblue has.

Franco Cozzo · 05-02-2021, 11:45 PM

Quote:

Originally Posted by aussiblue

Here's a copy of the page from the Briggs and Stratton Factory Workshop Manual. And if think that is crude, they also use a special knurling tool to knurl a pattern on worn cylinder walls to reduce their internal diameter. You need a different mind set when dealing with these cheap motors compared to car engines etc, They always were cheap and relatively disposable even made in the USA now being made in China they are even cheaper and more disposable. So yes usually it's cheaper and more sensible to buy a new mower than buy any parts costing more than a few dollars. But I know where you are coming from and I have to admit I keep repairing old mowers that I never use just for the fun of it. I use a Ryobi rechargeable one these days; lighter and much quieter and more reliable. In fact it's so light and easy to use the missus does the mowing for me now.

What's the opinion on electric lawn mowers?

In theory it should have instant torque but I see they use 2x 18V lithium ion batteries that a drill uses and I'm very suspicious on how effective that would be as it's not much juice at the end of the day.

**aussiblue** · 05-02-2021, 11:51 PM

Quote:

And its amazing what info aussiblue has.

Reasons:
1. Doing a quick prowl of the few bookshop in Perth most lunchtimes looking for bargains for the 50 years odd before I retired.
2. Being brought up in relative poverty on a dairy farm in a very isolated part of W.A. (Northcliffe) where if anything broke down it was fix it yourself or go without.
3. No TV in Northcliffe at the time either so reading and collecting books was ingrained.
3. Perhaps/maybe I am a bit of a hoarder too. Well My missus thinks so but I am not convinced.

**aussiblue** · 05-02-2021, 11:57 PM

Quote:

What's the opinion on electric lawn mowers?

Both my son and I have them and we would never go back to petrol. I have the Ryobi and he has an Ozito. Very easy to use and no messing about with fuel or oil or starters. They do everything my old Scott Bonner 5 hp Briggs and Stratton powered one did with much less fuss. I have this one https://www.bunnings.com.au/ryobi-on...r-kit_p3381291 the Ryobi One+ 18V 4.0Ah 36cm Lawn Mower so a single battery that usually suffices for the front or back lawn but also I have lots of spare batteries from a several Ryobi gardening One+ tools we have if they are needed. The mowing strip width is narrower than mu old petrol machine but the lighter weight and extra maneuverability means it takes no longer to mow the lawn.

My son has this two battery Ozito https://www.bunnings.com.au/ozito-px...r-kit_p0244221 ; it's heavier than the Ryobi and awkward to change the cutting height.

**GasoLane** · 06-02-2021, 12:50 PM

Quote:

Originally Posted by Franco Cozzo

What's the opinion on electric lawn mowers?

In theory it should have instant torque but I see they use 2x 18V lithium ion batteries that a drill uses and I'm very suspicious on how effective that would be as it's not much juice at the end of the day.

I bought an EGO self propelled kit (coz I'm lazy.)

57v. 5ah battery which lasts for about 40mins, 30 min recharge time.

The downside is the kit (Mower/battery/charger) costs about twice the price of a petrol mower.

wodahs · 06-02-2021, 01:40 PM

Quote:

Originally Posted by Franco Cozzo

What's the opinion on electric lawn mowers?

my opinion ~ i wish two of my neighbours had them when they decide to mow at 7am on the weekend . its always a joy to know that they are up

Franco Cozzo · 06-02-2021, 01:47 PM

Quote:

Originally Posted by wodahs

my opinion ~ i wish two of my neighbours had them when they decide to mow at 7am on the weekend . its always a joy to know that they are up

That's alright, invite them to your 1990s Eurodance dance party at 2AM this upcoming Thursday

hayseed · 06-02-2021, 01:53 PM

Quote:

Originally Posted by Franco Cozzo

That's alright, invite them to your 1990s Eurodance dance party at 2AM this upcoming Thursday

They'll Probably even Throw rocks through your Windows , So they can hear the music better...

123Cat · 08-02-2021, 08:09 PM

Blue EA

Ive got an Ed

Yes try that as they say , should work and cool it maybe in dry ice ,before assembly and also heat the ally part , this will really help it lock in

A simple valve regrind in ,,,,,,,,and hone the cylinder,,,,,, with cross hatching,,,,,,, with some emery paper , by hand , and hard scrub with detergent , and your ultrasonic cleaner is probably not big enough to put the inserted valve seat and cylinder in , so a hard scrub with detergent

A really good project