I have a problem with this mower- one cylinder is running rich. The mower runs fine and it's only when checking the plugs that the problem is apparent: one plug is black, the other shows perfect burning. I've replaced the plugs and removed the carb and stripped it down and checked the jet is clear. Without success. Any suggestions? Does this engine have conventional valves, and is so might the tappet clearance have closed up?
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Honda 2620 ride on mower with v twin 20 engine,
- Thread starter Skodajag
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Export threadshiftsuper175607
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I have a problem with this mower- one cylinder is running rich. The mower runs fine and it's only when checking the plugs that the problem is apparent: one plug is black, the other shows perfect burning. I've replaced the plugs and removed the carb and stripped it down and checked the jet is clear. Without success. Any suggestions? Does this engine have conventional valves, and is so might the tappet clearance have closed up?
what about checking the valve clearances?
bertsmobile1
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Yep,
A conventional engine 2 valves per cylinder pushrods and rockers.
Valve lash should be checked every 200 hours or there abouts.
A conventional engine 2 valves per cylinder pushrods and rockers.
Valve lash should be checked every 200 hours or there abouts.
Yep,
A conventional engine 2 valves per cylinder pushrods and rockers.
Valve lash should be checked every 200 hours or there abouts.
Thankyou. I'm checking valve clearances now. Any idea what the valve clearances should be?
So far I've eliminated the following as the possible cause:
Plugs (replaced)
Air filter (replaced)
Tappets/valve clearances (adjusted)
Carburettor (removed, jet cleaned, one O ring replaced)
The engine actually runs perfectly - even tickover, revs cleanly, no misfire or smoke - but always one plug is black while the other looks to be burning perfectly (brown/grey)
My local Honda agent wants to replace the coils but I can't see how the engine would run so well if one or both coils were faulty.
I'm perplexed!
Plugs (replaced)
Air filter (replaced)
Tappets/valve clearances (adjusted)
Carburettor (removed, jet cleaned, one O ring replaced)
The engine actually runs perfectly - even tickover, revs cleanly, no misfire or smoke - but always one plug is black while the other looks to be burning perfectly (brown/grey)
My local Honda agent wants to replace the coils but I can't see how the engine would run so well if one or both coils were faulty.
I'm perplexed!
shiftsuper175607
Lawn Addict
- Joined
- Sep 11, 2013
- Threads
- 10
- Messages
- 1,000
So far I've eliminated the following as the possible cause:
Plugs (replaced)
Air filter (replaced)
Tappets/valve clearances (adjusted)
Carburettor (removed, jet cleaned, one O ring replaced)
The engine actually runs perfectly - even tickover, revs cleanly, no misfire or smoke - but always one plug is black while the other looks to be burning perfectly (brown/grey)
My local Honda agent wants to replace the coils but I can't see how the engine would run so well if one or both coils were faulty.
I'm perplexed!
Sounds like a good cure to your problem would be to stop pulling the spark plugs and looking at them.
Sounds like a good cure to your problem would be to stop pulling the spark plugs and looking at them.
Ah, but that's a New World solution. I live in the Old World. Beleaguered by Anxiety.....
bertsmobile1
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If it is running fine then leave it alone.
Black deposits on a plug can be
too rich , exhaust valve not opening far enough :- normally sooty & dry
Faulty spark timing or spark ;- similar but damp
Oil leaking down the inlet valve or through head gasket :- wet, shiny and lumpy
You can usually check for this by pulling the manifold off and looking at the underside of the valve.
Should look like staining on a chrome exhaust pipe, if there is any build up then the seal is gone.
Black deposits on a plug can be
too rich , exhaust valve not opening far enough :- normally sooty & dry
Faulty spark timing or spark ;- similar but damp
Oil leaking down the inlet valve or through head gasket :- wet, shiny and lumpy
You can usually check for this by pulling the manifold off and looking at the underside of the valve.
Should look like staining on a chrome exhaust pipe, if there is any build up then the seal is gone.
Sounds like a good cure to your problem would be to stop pulling the spark plugs and looking at them.
LOL.
If it runs fine, don't mess with it.