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Honda Harmony II won't start


Lamarth's Avatar
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08-16-07, 04:55 PM   #1  
Honda Harmony II won't start

Hi-

Got a 'hand me down' Honda Harmony II from a friend. The 'you fix it it's yours' sort of deal He told me that he got it out this spring, mowed the lawn once and it wouldn't start again. Didn't even try to fire, it'd just spin as you pull the start cord. Not being very mechanically inclined, he went out and got a new mower.

So I took a crack at it since my old 12- year old mower bit the dust a few weeks ago (and this thing's only 2 years old). I did the following:

Changed spark plug and gas
Removed carb and cleaned it (it was surprisingly clean, no sediment at all found - probably didn't need it)
Checked for compression by removing the plug and covering the hole with a finger. Seems good- got a lot of blow-by and vacuum.
Shot some starter fluid into the carb (not too much though, since I'm not dealing with a auto engine) but didn't even act like it wanted to 'catch'

Then I checked the ignition coil - while I was getting a spark the spark seemed rather weak - and found that the spark plug wire had a gash about halfway thru the wire. So the coil got replaced but that didn't help at all :/

My friend swears that the engine ran fine before it stopped on him, but I'm running out of things to try. Any ideas?

Thanks!
David

 
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08-16-07, 05:31 PM   #2  
Of the three areas of concern, you've covered two quite well, it appears...Carburetion and ingition. Now you need to be concerned with the third, compression. Your finger test is fair but not too accurate and you need to, at a minumum, test compression with a gauge or, even better, test the combustion chamber with a leak-down tester. The leak-down test will be more accurate in determining where, if at all, you have trouble. I'm going to guess you have an intake valve clearance issue with such being excessive and possibly the exhaust being tight or nonexistant. Is this an overhead valve engine or an overhead cam engine?

 
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08-16-07, 07:07 PM   #3  
Posted By: puey61 Is this an overhead valve engine or an overhead cam engine?
It's a overhead-cam engine. I don't know the engine model number but the mower's number is HRR216S3DA
So it sounds like it might be a sticking valve then, or the valve lash being out of adjustment (like WAY out of adjustment :/) ?

I can probably get ahold of a compression tester over at the local auto store.

 
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08-17-07, 09:31 AM   #4  
I managed to find the Owner's Manual to my mower which gives the valve lash values- but what is the procedure to check/set the lash on this engine?

 
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08-17-07, 04:31 PM   #5  
While it would be good to know how I need to check the valve lash, I found the problem....

The timing belt 'jumped' off the camshaft sprocket. Two things come to mind:

1) What would cause that? If I simply put it back on the sprocket, what's to prevent it from coming off again?

2) How do I put it back on? I assume I can just slip it back on but how do I set the timing between the crank and the camshaft?

Again- thanks!
David

 
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08-17-07, 05:42 PM   #6  
Way way way out of my league here but gotta take a stab at it. No idea how old it is but if it has a timing belt, belts are by nature going to either break or stretch. That would make sense toward puey's diagnosis because that would throw off both intake and exhaust valve timing.

As for the questions, I would guess either age or wear would make it come off (other than mechanical issues) and there are probably some timing marks on the crank and cam drives to align when putting on the new belt.

ALL THAT BEING SAID THIS IS A GUESS.....I HAVE NEVER WORKED ON A MOWER WITH A TIMING BELT SO ......take my words with a grain of salt and hang in there for the experts....i'm just throwing out ideas here.

 
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08-17-07, 07:05 PM   #7  
No I appreciate the ideas - you might be right in that the belt may've stretched. IT's only a 2-year old mower so I'm surprised that the belt could've worn out that soon. I would've thought there'd be a tension pulley to keep the slack out but I somehow doubt it in this small an engine.

Of course then I would have to ask the question - how do I change the belt out? I'm not afraid of opening up the engine- I'll do that if I have to. But if I have to do that then I'll need to know how that's done also....

 
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08-18-07, 12:11 AM   #8  
Before you get too far into this, take a look at the valve cover. Is there a dent in it at all? If so, this may be the entire problem. The valve cover is very thin metal, and dents easily when the mower is pushed under a low obstacle and the valve cover hits the object. This cover fits closely over the rocker arms, and if it gets dented, it stops the rocker arm from travelling the full range of travel, and often holds the valve open just enough to keep the engine from starting.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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08-18-07, 08:00 AM   #9  
Nope- no dents. Checking both the inside and outside of the cover it looks to be in excellent shape.

 
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08-29-07, 06:07 PM   #10  
Well I got the mower to start and run, but it occasionally surges- not badly but enough to be annoying. It'll do this for about 10-15 seconds then evens out. Seems to do it at random intervals of roughly twice every minute.

I've tried adjusting the air/fuel mix screw but it didnt' help- couldn't turn it much anyway because of the limiting cap. Also, when it does it I'd watch the governor link and it wouldn't move at all while this is happening.

I've already cleaned out the carb earlier when I was trying to get the engine to start- and it was pretty clean then (no sediment in the bowl) so I doubt tearing it down again would help. The plug looks ok- white porcelin near the electrode, grey soot everywhere else and it's been gapped correctly.

Any suggestions on where to start?

Thanks!
David

 
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08-30-07, 04:25 PM   #11  
The surging could be caused by a loose intake bolt or a damaged intake gasket.

 
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08-30-07, 04:34 PM   #12  
Clean out the main jet again.

 
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