Honda 50 lost compression

[Fred Fry]

I am kinda baffled about what happened.
I have a honda gxh 50 on a friction drive and this is my second year and it has been great.
It probably has about 100 hrs. on it.
It has always started on the first pull when cold with choke.
Yesterday morning I pulled it 4 times and nothing.
The previous day it was running great.
I found it was getting gas and spark.
I pulled the spark plug and put my finger over the hole and felt no compression.
I poured a little oil into the cylinder and the compression got better.
I put the plug back in and it started right up.
Now it is starting again on the first pull like before.
I have been running on synthetic oil.
Were my rings carboned up and stuck?
Should I put something in the motor to clean it out?

Thank You Fred

 

[scotto-]

Valve?

You may have had a valve sticking (open or closed), but a ring sticking would be a seizure of such and oil wouldn't improve the compression much in that case. Valve sticking...perhaps.

 

[GearNut]

I would add 1/2 a teaspoon of Marvel Mystery oil to it. It helps clean out carbon gunk from the ring lands in the piston, and any carbon or gunk built up around the valve guides.
Do not use too much! If misused, it can do more harm than good.

 

[Old Bob]

Stuck rings don't loosen that quick.
I don't recommend putting marvel in that engine. It uses splash lube and has no filter. Marvel is high detergent,it will loosen particles and gunk only to have it redistributed in other places.
Pull the valve cover and see if there any build up,varnish etc.

Hard to beleive running syn that theres gunk built up already.
How often do you change it?
When was the last time you adjusted valves?

 

[Fred Fry]

Hi old bob,
I adjusted the valves about 2 weeks ago.
They were sloppy like one was .008 and the other was.012.
I adjusted them to .003.
Everything looked clean under the valve cover.
She's back to her old self starting on the first pull.
I am thinking something caused the valves to stick open.
I have heard running some trans fluid for a short time and then to do an oil change.
I change the oil often. It takes very little oil and the cost is minimal.
Thank You
Fred

 

[Old Bob]

I've seen this on a couple of engines with some hours.
Its possible for the exhaust valve to stick if it had been running with a lot of lash, a ring of varnish forms on valve stem, when the lash is tightened the ring is pushed into guide and can stick valve, most of the time the ring rubs off and everything is ok.
This could be a possibility in your case.

If the engine is fairly clean then regular cleaning with marvel or ATF will keep it clean and won't hurt it.Only when theres sludge build up that I would avoid it, in that case I pull it apart and clean it in degreaser.

 

[unior]

old bob:

is the head gasket reusable on this engine and/or the huaseng 50?

 

[Old Bob]

old bob:

is the head gasket reusable on this engine and/or the huaseng 50?

GXH50 does not have a head gasket,the head is integral with cylinder/crank case.

 

[unior]

GXH50 does not have a head gasket,the head is integral with cylinder/crank case.

Ooops, duh. How difficult is it to remove the valves? How much dissasembly is required?

tia
unior

 

[scotto-]

Complete dissasembly

It's not that difficult to remove the valves, it's a lot more difficult putting the whole engine back together without the knowledge, the proper tools, a shop manual and a good memory. You have to split the crankcase halves to access the valves which means almost complete dissasembly of the engine.

It's really not that hard if you know what you're doing.