Use to run now it won't
Posted January 09, 2012 - 09:25 PM
I started with a new old HH100 engine same model as in the Massey but the engine was for a Wheel Horse. When I tried to run the engine out of the GT it would not start do to a stuck ex valve. It probably rusted from sitting so long in a shed. I got the valve freed up and the engine started fine. So I cleaned the engine up and painted it. I put it back in the Massey and it would not run. It would fire once in a great while but not run. I had fire, I had gas at the carb. I changed plugs I even shot some starting fluid in the carb no luck. So I took the carb apart and yes I removed the main jet. After reading some threads about Walboro carbs I remembered the service nozzle issue. I took the nozzle back out and machined a grove like the service nozzle put it back in still no luck. I checked the compression and it was ok but not what I thought it should be. But when I held my hand in front of the carb it would suck my hand up to it.
Today I stopped at my lawn mower shop and told the mechanic what was going on and to see if they had a service nozzle, they did so I bought it. He said it was timing and he bet it back fired and sheared the flywheel key. Not wanting to scuff up the paint I tried shooting penetrating oil in the Ex valve, no luck. So I took the shroud off and took the flywheel off, the key was fine. So while I was that close I took the head off and removed both valves and cleaned them. The ex valve had some sticky stuff on the stem and it did not feel like it was closing all the way. I thought I had found the problem. I went ahead and lapped them while I had them out and checked the clearance. I put it all back together expecting it to run. No luck, no change at all. It does fire every once in a while but when it does it backfires through the carb. So when all else fails read the service manual. It said to check the ohms of the coil, to do this I had to take the shroud off again. So I took it off and checked it, 477 ohms, with in specks, I checked a new coil and it was 469 ohms. I checked the air gap and it is within specs. So now what do I do. To recap I have fuel to the carb, I have spark at the plug and trough the plug, I have good compression. This motor ran fine before I painted it. I am lost as to what to do next.
Posted January 09, 2012 - 09:39 PM
When I have an engine that seems to have everything but noise, I double check myself. $5 inline spark checker shows spark. Both gaskets between the carb and engine in place, compression where it should be, etc. Then I try some carb cleaner in the intake. (Make sure the choke is open... Man that stuff stings)
If the plug is wet and no noise, I find anything but a Champion and put it in. This often solves the problem.
Another thing I've done, ran propane into the air intake. More than once I've had this prove to me an engine will run... I'm just missing something... Like a mal adjusted carb or plugged jet I missed. Don't do this for more than a couple of seconds, then only after putting a few drops of something lubricant like in there.
BTW, I believe the compression check on that engine will read around 55-60 because of the compression release.
Posted January 09, 2012 - 09:40 PM
Posted January 09, 2012 - 09:42 PM
Posted January 09, 2012 - 09:51 PM
The one thing I keep going back to is it ran fine before I painted it.
Posted January 09, 2012 - 09:51 PM
Posted January 09, 2012 - 09:56 PM
The head gasket is good, I had one that was missing some of the material between the 2 outer layers of metal, really hard to see but you could feel air leak out on compression stroke, that engine would almost start with that bad head gasket.
Edited by DH1, January 09, 2012 - 10:02 PM.
Posted January 09, 2012 - 11:10 PM
It has to be something simple that I am missing. It ran fine and now it doesn't, nothing was changed except the paint.
What part does the stator/coil play in the ignition and is the rectifier part of the ingition?
Edited by DanP, January 09, 2012 - 11:16 PM.
Posted January 10, 2012 - 07:44 AM
Posted January 10, 2012 - 08:18 AM
Posted January 10, 2012 - 09:40 AM
Posted January 10, 2012 - 10:05 AM
If all that you did is paint it did you check all the connections?
or disconect all of your connections except the starter. It should run on it's own. Maybe your connections are partially grounding out the coil?
Posted January 10, 2012 - 10:35 AM
Posted January 10, 2012 - 10:58 AM
What kind of shape is your plug wire in? If it's really old it could be broken and disconnected when it's in the plug hole and then makes a connection when you pull it out to test it. broken wires can do that when you flex them. Also, some of these guys are talking about valve and head gasket problems... Sounds like a good time to get a compression test done and then hunt that down if it's low.
Posted January 10, 2012 - 03:51 PM
I will check all the connections but they were taped up when I painted it. I have spark so I don't think it is grounding out the coil. I am going to run a ground wire from the battery to the rectifier case to the motor tonight to make sure I have a good ground. I may not with the heavy coat of paint and clear coat. That is the only thing I can think off that the paint would have caused. But I still have spark maybe just not good enough. I did disconnect the rectifier as I was trying to start it as I had a battery charger hook to the battery.
The SSI uses ground to shut it down. That is why I suggested disconnecting all the wires, then try and start it. I had a SSI that produced spark, but it wasn't enought spark to make it run. I replaced the SSI and it started and ran great.
If that ground wire on the SSI touches 12 volts for even a second, it will kill the SSI.