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Generator Engine Trouble

Started by Ga Mtn Man, December 15, 2017, 08:57:57 AM

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Ga Mtn Man

I have a small 3200 running watt Chinese-made generator (similar to Harbor Freight gens) that has run flawlessly for quite a few hours over the last 3.5 yrs.  The other day I inadvertently way over filled the oil.  When I started it, it jerked back badly on the recoil starter rope and then ran horribly, RPMs surging up and down almost like it was running out of fuel (It had been running fine most of the prior two days during a power outage).  I shut it off, discovered what I had done, drained the excess oil and restarted it.  Same as before, hard jerk back on the rope and surging RPMs.  I left it overnight hoping it would fix itself.  Nope. 

I don't know all that much about these small engines except how to clean the carb and change the oil and plug.  What damage might I have done by over filling the oil?
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

Kbeitz

Sounds like you twisted the flywheel key...
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

sawguy21

You have hydraulic lock, oil has worked it's way past the rings. Remove the spark plug and with the switch off pull the rope a half dozen times. don't be peering down the spark plug hole when doing this ;D  It will smoke so let it run. Make sure the air filter is not saturated.
old age and treachery will always overcome youth and enthusiasm

Ga Mtn Man

Pulled the flywheel and the key looked good.

sawguy21-  It may be too late for that...I let the engine run about 15 minutes yesterday hoping it would "burn off" the excess oil.  After 15 minutes it still wasn't running right.  I shut it off, pulled on the starter and it jerked hard against me.  Hope I haven't ruined the engine.   :-\
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

starmac

If the engine ran, it was not hydrolocked. How much oil did you overfill it, it is possible that you could have damaged the bottom of the piston if it was slapping the oil, but that is way overfull.

How low on oil was it when you originally added oil, is it possible that you ran it low and scored the piston?
Old LT40HD, old log truck, old MM forklift, and several huskies.

Ga Mtn Man

The oil was just below the L on the dipstick.  The engine does have a low oil shutoff.
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

DelawhereJoe

My F.I.L put 3 qts into a 18.5 hp brigs motor and then tried to start it, it didn't run so well afterwards. It ended up smoking for the rest of its life but did run and fogged for mosquitoes at the same time. Did the oil blow up the breather line into thd carb or by running all oily did it gum up the spark plug or muffler ?
WD-40, DUCT TAPE, 024, 026, 362c-m, 041, homelite xl, JD 2510

starmac

Not a lot of things could make it hard to pull, if it built some carbon on top of the piston, it would. A stopped up muffler could, but that would be major stopped up.
pull the plug and pull the rope, if it isn't internal, it should have nearly no resistance, if still hard and jerky, pull the head and check (hope) for carbon build up.
Old LT40HD, old log truck, old MM forklift, and several huskies.

Kbeitz

Quote from: Ga Mtn Man on December 15, 2017, 02:20:36 PM
Pulled the flywheel and the key looked good.

sawguy21-  It may be too late for that...I let the engine run about 15 minutes yesterday hoping it would "burn off" the excess oil.  After 15 minutes it still wasn't running right.  I shut it off, pulled on the starter and it jerked hard against me.  Hope I haven't ruined the engine.   :-\

If it jerk back against it still sounds like a key that off set just a tad.
If the key is good then I'm betting you twisted the crank a tad. This
off sets the timing causing the kick back.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

starmac

Jerking back does sound like the timing. I tend to think a guy would break the rope before it would twist the crank. I also do not think you would get a one cylinder to crank and run if it was hydrolocked with oil. larger engines will start with just liquid on one cylinder, but it will either blow the head gasket, or bend a rod even before the engine cranks if the starter is strong enough.
Old LT40HD, old log truck, old MM forklift, and several huskies.

Ljohnsaw

 popcorn_smiley  I've always read not to over fill and wondered what would happen.  I assumed that you would just blow the oil seal on the crank shaft.  Hope you find the solution or at least what is "broken" now.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Kbeitz

Quote from: starmac on December 15, 2017, 11:28:55 PM
Jerking back does sound like the timing. I tend to think a guy would break the rope before it would twist the crank. I also do not think you would get a one cylinder to crank and run if it was hydrolocked with oil. larger engines will start with just liquid on one cylinder, but it will either blow the head gasket, or bend a rod even before the engine cranks if the starter is strong enough.

The rope is not what twist the crank. It's when you pull the rope and the piston
slams up against the oil and everything comes to a screeching stop. The weight
of the flywheel can easy shear a key and even snap off the end of a crank.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Don P

To get oil on top of the piston it had to slam down into oil and get by the rings? Then back up and try to compress it against the head? Is a compression check due?

Kbeitz

Quote from: Don P on December 16, 2017, 07:27:46 AM
To get oil on top of the piston it had to slam down into oil and get by the rings? Then back up and try to compress it against the head? Is a compression check due?

It can also come up through the breather.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

DelawhereJoe

Yes, yes it can. I worked on a friends 5hp leaf and branch chipper that had sat outside for the last 1.5 years, well the rain had made it down into the crank case via the muffler ( unknown to me) and once I started pulling the starter handle it pumped white oil/water right into the carb from the breather line.
WD-40, DUCT TAPE, 024, 026, 362c-m, 041, homelite xl, JD 2510

Ga Mtn Man

I thought I'd let you guys know what I found.  Two FF members suggested that the  "auto compression release mechanism" might have been damaged due to the high oil level.  After watching a bunch of youtube videos to figure out how to get the generator rotor off of the engine, I managed to get it off without too much cussing and then opened the crank case.  I found the aforementioned mechanism on the cam shaft intact and working properly and did not see any obvious issues inside the crank case.  I then pulled the head off to see what was going on there.  There was a very thick burnt oil deposit on the piston and head, which I cleaned off.  The valves and seats looked in good shape.  While I was putting it all back together I discovered that the exhaust valve rocker stud(the thing the rocker arm mounts to and pivots on) was loose and had backed out about half a turn.  Hmmm...  I tightened it up and checked the other one, reset the valve clearances, and put the whole thing back together, which is no small task.  It started easily with one pull and ran like new!

In my original post I said that it "had been running fine" the previous day.  I now recall that I had noticed the engine sound changing during the second day of running but I didn't think much of it and just shut if off when the power came back on.  I think the change in the engine sound was probably from the rocker stud loosening and that is what caused the problems I had when I went to start it again after changing the oil.  I don't think over filling the oil had anything to do with the problem.  Not sure of that though.

Thanks for all the help!


     
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

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