Hi All,

Following on from my previous thread...

Firstly the good news....
I have just fitted a new diaphragm and head gasket to the mower and it runs much better than before. No hunting and seems to running "quicker" than before. I haven't tried it under load yet though...

Now the bad news....
1. Although it runs OKish, now and again it does a "cough"
2. On starting, it still pumps out a cloud of black smoke although after this one blast, smoke is colourless
3. When I refitted the head, one of the bolts snapped so it is currently one down!
4. I cleaned all the engine etc. and whilst at it, thought I would clean the exhaust. Stupidly, I hadn't realised it had baffles (or similar) in it so poured some petrol in to clean it. Petrol disappeared (assume it got absorbed by the stuff in the exhaust!).

Only other info I can think of which might be relevant is that I regapped the plug to 0.030" which I got from the B+S website...

Any ideas? I think I am ready to throw in the towel

thanks

Lee.

On 14/07/2012 17:55, Lee Nowell wrote:
Hi All,

Following on from my previous thread...

Firstly the good news....
I have just fitted a new diaphragm and head gasket to the mower and it runs much better than before. No hunting and seems to running "quicker" than before. I haven't tried it under load yet though...

Now the bad news....
1. Although it runs OKish, now and again it does a "cough"
2. On starting, it still pumps out a cloud of black smoke although after this one blast, smoke is colourless
3. When I refitted the head, one of the bolts snapped so it is currently one down!
4. I cleaned all the engine etc. and whilst at it, thought I would clean the exhaust. Stupidly, I hadn't realised it had baffles (or similar) in it so poured some petrol in to clean it. Petrol disappeared (assume it got absorbed by the stuff in the exhaust!).

Only other info I can think of which might be relevant is that I regapped the plug to 0.030" which I got from the B+S website...

Any ideas? I think I am ready to throw in the towel

thanks

Lee.
You really need to get the snapped bolt sorted before looking at
anything else. Did you use a torque wrench for tightening? generally
people with no `engine` experience will over tighten bolts.
It is possible to to get the snapped bolt out DIY but if you are not
sure or confident then almost any motorbike repair shop will do it.

On Sat, 14 Jul 2012 09:55:21 -0700 (PDT), Lee Nowell
wrote:

3. When I refitted the head, one of the bolts snapped so it is currently one down!

Well, the engine's buggered, then. You can't just ignore a cylinder
head minus one bolt! Also, the head will warp - maybe it has already.

MM

It depends very much on where the bolt is that snapped. I'm worried about
the snapping on fitting, if it snapped on extraction then its probably worth
getting it sorted, but overtighteneing on fitting is not a good idea at all
as all the bolts will now be suspect if not tightened to the right factory
settings. I've seen the results of this sort of thing back when I was young,
cracked heads, damaged blocks and warped parts that no gasket can fix.

Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"MM" wrote in message
...
On Sat, 14 Jul 2012 09:55:21 -0700 (PDT), Lee Nowell
wrote:

3. When I refitted the head, one of the bolts snapped so it is currently
one down!

Well, the engine's buggered, then. You can't just ignore a cylinder
head minus one bolt! Also, the head will warp - maybe it has already.

MM

On 15/07/2012 09:11, Brian Gaff wrote:
It depends very much on where the bolt is that snapped. I'm worried about
the snapping on fitting, if it snapped on extraction then its probably worth
getting it sorted, but overtighteneing on fitting is not a good idea at all
as all the bolts will now be suspect if not tightened to the right factory
settings. I've seen the results of this sort of thing back when I was young,
cracked heads, damaged blocks and warped parts that no gasket can fix.

Brian


Based on the fact the engine is actually running I would attempt a fix
on the bolt. Yip the head could be warped etc but if you can get it
running and cutting grass what the hell give it a bash.

On Jul 14, 5:55*pm, Lee Nowell wrote:
Hi All,

Following on from my previous thread...

Firstly the good news....
I have just fitted a new diaphragm and head gasket to the mower and it runs much better than before. *No hunting and seems to running "quicker" than before. I haven't tried it under load yet though...

Now the bad news....
1. Although it runs OKish, now and again it does a "cough"
2. On starting, it still pumps out a cloud of black smoke although after this one blast, smoke is colourless
3. When I refitted the head, one of the bolts snapped so it is currently one down!
4. I cleaned all the engine etc. and whilst at it, thought I would clean the exhaust. *Stupidly, I hadn't realised it had baffles (or similar) in it so poured some petrol in to clean it. *Petrol disappeared (assume it got absorbed by the stuff in the exhaust!).

Only other info I can think of which might be relevant is that I regapped the plug to 0.030" which I got from the B+S website...

Any ideas? I think I am ready to throw in the towel

What manufacturer would put a bolt that easily clapped on his engines?

You might want to tell them someone has been flogging them china.

Yes, fine but I'm also a bit alarmed at pouring petrol into exhausts. I mean
it went somewhere obviously not the intended outcome.
also smoke at start tends to suggest there still is somewhere where the
muck persists.
I guess its the old right said fred syndrome of fixing things. No real
excuse now we have the Internet. I know someone who trashes generators by
doing daft things like wrong oil and tweaking.. shudder.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"ss" wrote in message
...
On 15/07/2012 09:11, Brian Gaff wrote:
It depends very much on where the bolt is that snapped. I'm worried about
the snapping on fitting, if it snapped on extraction then its probably
worth
getting it sorted, but overtighteneing on fitting is not a good idea at
all
as all the bolts will now be suspect if not tightened to the right
factory
settings. I've seen the results of this sort of thing back when I was
young,
cracked heads, damaged blocks and warped parts that no gasket can fix.

Brian


Based on the fact the engine is actually running I would attempt a fix on
the bolt. Yip the head could be warped etc but if you can get it running
and cutting grass what the hell give it a bash.

I guess the question is where it is coming from. Having completely cleaned everything when i took the engine apart, the only thing that hasnt been cleaned is the exhaust. Well least i tried tooooooo

Anyone any thoughts on the coughing? Could this be an issue with the exhaust being 'blocked'?

Thanks

Lee.

Lee Nowell wrote:
I guess the question is where it is coming from. Having completely cleaned everything when i took the engine apart, the only thing that hasnt been cleaned is the exhaust. Well least i tried tooooooo

Anyone any thoughts on the coughing? Could this be an issue with the exhaust being 'blocked'?

usually a sign of weak mixture/sticking valve/advanced ignition...

If the head is held down by less screws then it may be warped causing te
valve to jam.

Thanks

Lee.


--
To people who know nothing, anything is possible.
To people who know too much, it is a sad fact
that they know how little is really possible -
and how hard it is to achieve it.

The Natural Philosopher wrote:
Lee Nowell wrote:
I guess the question is where it is coming from. Having completely
cleaned everything when i took the engine apart, the only thing that
hasnt been cleaned is the exhaust. Well least i tried tooooooo
Anyone any thoughts on the coughing? Could this be an issue with the
exhaust being 'blocked'?
usually a sign of weak mixture/sticking valve/advanced ignition...

If the head is held down by less screws then it may be warped causing te valve to jam.

Thanks
Lee.


Unlikely I would have thought as most lawn mower engines are side-valve.

Tim

Tim wrote:
The Natural Philosopher wrote:
Lee Nowell wrote:
I guess the question is where it is coming from. Having completely
cleaned everything when i took the engine apart, the only thing that
hasnt been cleaned is the exhaust. Well least i tried tooooooo
Anyone any thoughts on the coughing? Could this be an issue with the
exhaust being 'blocked'?
usually a sign of weak mixture/sticking valve/advanced ignition...
If the head is held down by less screws then it may be warped causing te valve to jam.

Thanks
Lee.


Unlikely I would have thought as most lawn mower engines are side-valve.

Tim
can still warp the cylinder.

But I am fairly sure my B & S says OHV on it somewhere.


--
To people who know nothing, anything is possible.
To people who know too much, it is a sad fact
that they know how little is really possible -
and how hard it is to achieve it.

The valves on mine are next to the piston. All moving from front to back.