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regwal (87)
2021/04/19 13:13:20
gritche

Powermore engine only runs on choke

I'm in need of other ideas on what to check on that case:
 
Engine only runs on choke. I tried 3 cleaned carburators, all the same. Valves are in specs. Compression reads around 160-170. Fresh gas, new sparkplug, checked if muffler was plugged, flywheel key OK.
 
I have a bit of air coming from the intake valve when I do a leakdown test but otherwise the engine holds pressure very well, I'm talking 5% loss here.
 
I don't have alot of experience with this particular chinese engine. Any other thing I should check before removing the head (if its even worth it at that point)?
 
Thanks alot
8 comments Leave a comment
AVB
Going to need more info about the engine like the model number at least. Both Briggs and MTD used the Powermore name for a while.
2021/04/20 08:49:06
gritche
This is annoying.
The only thing I can find on the engine is the family:
EF: ACZHS.1391V1
Can't find any parts/schematics on that engine
 
Those 139cc have been very common on mowers between 2005-2015 I'd say. If you want I can try to post a picture of the engine.
 
The mower is a yardworks, model: 11A-08M9515
2021/04/20 11:12:23
AVB
Then it is a 5P65M0 engine. (P65 MTD engine)
 
Your compression numbers are way out of line as it should not be above 95 psi. Either your valve are out of adjustment or the ACR on the camshaft has failed. This should be corrected first.
 
Intake .003 - .005
Exhaust .005 - .007
 
IF turns out to be the camshaft ACR then it is a junk engine as it would to be short blocked. Just better off buying another mower.
 
 
2021/04/20 12:25:53
gritche
The compression number is the true compression. Im "bypassing" the ACR by turning the engine fast enough with a drill.
Gonna check the compression with the standard method tomorrow and report.
 
Thanks for the engine number!
2021/04/21 18:44:59
gritche
Aight I did a standard compression test on it and got 90psi.
2021/04/24 15:17:19
GBertolet
Most likley a fuel issue. A lean condition. Either a restriction somewhere reducing the fuel, or a vacuum leak. Either way the air / fuel ratio is off, and using the choke richens up the ratio, enough to allow the engine to run. I have experienced this already, and usually a thorough cleaning of the carb, resolves this iisue.
2021/05/22 08:44:23
gritche
Fuel is unrestricted. Unless I have 3 carb that all does the same trouble...
 
I think its the intake valve. Its leaking a bit. Its the only thing I can see at this point.
2021/05/27 12:36:07
gritche
Fuel is unrestricted, fuel line fine. Unless I have 3 carb that all does the same trouble...
 
I think its the intake valve. Its leaking a bit. Its the only thing I can see at this point.
2021/05/27 12:36:07

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