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Baza
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Quote Baza Replybullet Topic: Howard Gem 810
    Posted: 09 Jun 2013 at 12:40am
Hi Guys  I am looking for some help with my Gem fitted with the 810 Jap engine.
I bought this off of a man way back in Autumn of last year who said he had restored this particular machine, including overhauling the magnito completely.  Unfortunately due to the really bad weather conditions throughout most of last year the Gem simply got laid up until now.  I have gone to use it and it started on about the third swing and seems to run and drive okay, albeit quite a bt of backfiring and spitting flames out of the exhaust, however upon attempting to actually dig with the machine the engine peters out and dies if left in the digging position.  If you lift the blades out of the ground thereby taking the strain off of the engine it will drive all okay again until trying to dig once more.
I have had a horticultural repairers  have a look at it and he seems to think that the Carburettor is at fault, (running too rich) probably badly worn, but I was concerned that it was the mag that's not set up right, he disagrees.
What are your thoughts, any advice appreciated and does anyone know where I may be able to obtain a replacment Carb or parts for this Gem.
The guy I got it from is too far away to get back to.
Any help greatly  appreciated.
Thanks Baz
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series1gem
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Quote series1gem Replybullet Posted: 09 Jun 2013 at 8:11am
The first job I would do is to whip the head off and check the bore,and particularly the valves.from your symptoms I would almost guarantee that the exhaust valve and maybe the inlet needs regrinding.
If it isnt orange it isnt a rotavator
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will_haggle
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Quote will_haggle Replybullet Posted: 09 Jun 2013 at 9:57am
Have a go at squirting some Redex down the carburettor inlet with the engine running. Be prepared for quite a bit of smoke, though. This treatment has been known to clear a sticking exhaust valve.
6 months ago I couldn't even spell engineer - now I are one
Calne, North Wiltshire...
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will_haggle
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Quote will_haggle Replybullet Posted: 09 Jun 2013 at 9:58am
Is the 810 engine a twin? if so it aint a JAP, it's Howards own....
6 months ago I couldn't even spell engineer - now I are one
Calne, North Wiltshire...
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series1gem
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Quote series1gem Replybullet Posted: 09 Jun 2013 at 10:16am
Does the engine look like this. If so it is as Allan suggests Howard's own twin, be thoughtful about taking the head off on these as head gaskets are hard to obtain.
If it isnt orange it isnt a rotavator
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howardhoe
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Quote howardhoe Replybullet Posted: 09 Jun 2013 at 10:44am
I had a bit of a problem with mine way back and turned out it was the decompresser lever was just tickling the valves, backed it off a bit and was right. Then the other day was using it and the fuel tap wasn't letting enough fuel through and was running terrible and lacking power. Pulled the tap off and ran like a clock after that. Also worth checking is the timing set up. What you would do is take the exhaust off, then the front cover and check all the dots on the gears line up. But be careful. When i got my engine the previous owner had bought it as a non runner and spent ages trying to get it going. From what i hear same as the owner before him. Ended up sitting in his shed for over ten years before i bought it. Took the front cover off and all the gears lined up like they should. But straight away i could see it was lifting valves at the wrong time so i retimed the gears by using top dead center and the valve moving by feel. I got it where i thought it was right and started first swing of the handle. When i told the previous owner he was a little pissed!
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Baza
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Quote Baza Replybullet Posted: 13 Jun 2013 at 1:24pm

Hi Guys

Thanks for all the help I've received.  Went through most of the suggestions without removing the head (thought that would be a lst resort, re replacement gasket), without finding anything amiss.  Then took Carburettor off and tookk it apart.  Didn't try this earlier as the guy I had taken it too told me he had removed carb and ultra-sonically cleaned it as his first job (outside looked reasonably clean but inside proved that in fact nothing had been doe to it at all, so much for trusting people.  cleaned it thoroughly and discovered that the mixture screw had been backed out almost completely.  She started almost first swing and by trial and error and keep screwing the mixture screw it till it was hard in its housing, machine ran sweetly.  Tries it out in the ground and dug great with governer cutting in to aadjust engine speed relevant to strain on it.

It is an Amal 697/1 Carb and I have now emailed Amal to see if they do a refurb or even a kit as I'm sure mixture screw should not be screwed in tight to run properly.

Also wanted to show a picture of my machine here for identification  but not sure how to. Copy and paste wont work?

Many thanks once again.

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Charlie
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Quote Charlie Replybullet Posted: 14 Jun 2013 at 7:14am
Glad to hear it is running. See 'Help...' section of forum re posting photo's.
'Don't force it! Get a bigger hammer'
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SON OF THE SOIL
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Quote SON OF THE SOIL Replybullet Posted: 18 Sep 2013 at 9:33pm
HELLO HOWARED HOE
IM ONE OF THOSE PISSED OFF PEOPLE , IVE GOT A 180 TWIN THATS BEEN APART BY PREVIOUS OWNERS AND NOW TIMING MARKS DONT LINE UP OR MAKE SENSE , AND IM AT A LOSS WHAT TO DO TO RETIME / SET UP AGAIN . IS NUMBER 1 CYLINDER THE FRONT CYLINDER OR NEAREST FLYWHEEL ? .HAVE PUT TO TDC BUT CAMSHAFT GEAR MARKS ALL OVER THE PLACE AND JUST DON'T SEEM TO SEE HOW TO OVERCOME THIS .
THIS ENGINE'S PISTONS GO UP AND DOWN TOGETHER , NOT ONE UP AND OTHER DOWN SO I THINK IT IS A 180 HOWARD ENGINE.
REALLY WOULD LIKE TO GET LIFE BACK IN HER BUT STRUGGLING . HAVE YOU ANY ADVICE THAT MAY HELP ? .
MANY THANKS IN ADVANCE AND ALL BEST TO YOU .
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will_haggle
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Quote will_haggle Replybullet Posted: 18 Sep 2013 at 11:36pm
If they go up and down together it's a 360, just like most British twin motorcycles. turn it till both valves are closed at TDC, if the marks are way out, keep turning till the other pair of valves are both closed, see what the marks are like then..
6 months ago I couldn't even spell engineer - now I are one
Calne, North Wiltshire...
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Quote howardhoe Replybullet Posted: 19 Sep 2013 at 12:43pm
Originally posted by SON OF THE SOIL

HELLO HOWARED HOE
IM ONE OF THOSE PISSED OFF PEOPLE , IVE GOT A 180 TWIN THATS BEEN APART BY PREVIOUS OWNERS AND NOW TIMING MARKS DONT LINE UP OR MAKE SENSE , AND IM AT A LOSS WHAT TO DO TO RETIME / SET UP AGAIN . IS NUMBER 1 CYLINDER THE FRONT CYLINDER OR NEAREST FLYWHEEL ? .HAVE PUT TO TDC BUT CAMSHAFT GEAR MARKS ALL OVER THE PLACE AND JUST DON'T SEEM TO SEE HOW TO OVERCOME THIS .
THIS ENGINE'S PISTONS GO UP AND DOWN TOGETHER , NOT ONE UP AND OTHER DOWN SO I THINK IT IS A 180 HOWARD ENGINE.
REALLY WOULD LIKE TO GET LIFE BACK IN HER BUT STRUGGLING . HAVE YOU ANY ADVICE THAT MAY HELP ? .
MANY THANKS IN ADVANCE AND ALL BEST TO YOU .
 
I know where you are at. It is a 360 engine. I too thought mine was a 180 but turned out being a 360. I was looking at the manifold and that is why i thought a 180 but being two engines put together has some odd features. If you can't get your dots to line up then you will have to time it manually like i did. My marks never line up and that is what made the last owner get rid of it, he couldn't work it out. If yours is all original it should line up at some point and i would work on getting that right first. But if you can't like i couldn't try doing it manually. Work on one cylinder. Remove one cog, might be the magneto one that lets the others spin independantly but i can't remember. Turn engine and put piston to the top, you may need a bent piece of wire throught the spark plug hole to feel it. Then turn cam shaft so the exhaust valve is just shut and the inlet valve is just about to open. Then hold that position. Replace the missing cog making sure the magneto is in the position where the points are just opening. Then check the other cylinder by turning the engine over and seeing if the valves close when the piston is at the top. It might take a couple of times to get this combination right. At this point you may notice dots on the cogs lining up, if they are out a dot or two right it as it means you have it where it is meant to be. Then try a start. Don't despare if it doesn't start, if it doesn't swap the HT leads over as they might be on the wrong cylinder. Hopefully that helps a bit, or at least gives you a place to start.
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