Robin Subaru Engine Problems With Solutions

[MossRoad]

if only a moderator would help me change my name...

Mods do not have that ability. You can PM Muhammad and ask him. I think its been done before.

[3v0]

My towable backhoe came with a 7 hp robin engine. When the oil is low enough for the low oil sensor to activate the engine will fire once or twice when cranked then die.

It holds 600cc or .6 quarts of oil and the dip sticks are nearly horizontal which makes them difficult to read. When I first got the unit I messed around trying to get the oil level right using the dip stick. I gave up and drained then refilled it.

I do not have a lot of hours on it but it runs good and I am a little impressed on how clean the oil stays.

[Kent]

Problem: Engine started fine, drove tractor out of garage to make room for another project (didn't let it warm up), shut it down and let it sit outside in 20 degree weather four hours, now it won't start. Carb pops and a flame shoots out.

Checked spark (weak but visible), compression (only 90 lbs but equal on both cyls), replaced plugs, replaced gas line and filter (clear tube had a crack anyway) with fuel rated hose, removed and tested fuel shut off plunger (and power to it, verifying ignition switch was OK), checked float level (plenty of gas in there, nice and bouncy floats). Did the crazy thing and ran a hair dryer on the carb to melt any ice, thinking that because I didn't let the engine warm up before letting it sit that somehow ice crystals were blocking the jets (getting desperate here!). Cranking doesn't flood engine/soak spark plugs due to the flames ;-). This is the extent of my diagnostic capabilities.

Robin engine mechanic found that the stator assembly was "shot" and hence the timing was virutually crazy. Not that the timing slipped out of adjustment, but that the coils were blown, barely firing the plugs and at the wrong time. Nothing I could have figured out! Parts were relatively cheap (about a hundred after a trade in value) but the labor to pull the engine, make the repair, and replace the engine was 4.5 hours. Actually amazing he did this so quickly, given he had never seen a PT before...and also took the hyd pumps out with the engine, so all those hoses were removed as well.

Related post: http://www.tractorbynet.com/forums/p...tting-out.html

[Kent]

Update: Subaru said they will not cover the cost of the repair under their warrantee because the problem in their mind was due to overheating. So I guess you can count on their warrantee as long as the engine is working properly in perfectly cooled (but not cold) and sanitary environment.

Problem: Engine started fine, drove tractor out of garage to make room for another project (didn't let it warm up), shut it down and let it sit outside in 20 degree weather four hours, now it won't start. Carb pops and a flame shoots out.

Checked spark (weak but visible), compression (only 90 lbs but equal on both cyls), replaced plugs, replaced gas line and filter (clear tube had a crack anyway) with fuel rated hose, removed and tested fuel shut off plunger (and power to it, verifying ignition switch was OK), checked float level (plenty of gas in there, nice and bouncy floats). Did the crazy thing and ran a hair dryer on the carb to melt any ice, thinking that because I didn't let the engine warm up before letting it sit that somehow ice crystals were blocking the jets (getting desperate here!). Cranking doesn't flood engine/soak spark plugs due to the flames ;-). This is the extent of my diagnostic capabilities.

Robin engine mechanic found that the stator assembly was "shot" and hence the timing was virutually crazy. Not that the timing slipped out of adjustment, but that the coils were blown, barely firing the plugs and at the wrong time. Nothing I could have figured out! Parts were relatively cheap (about a hundred after a trade in value) but the labor to pull the engine, make the repair, and replace the engine was 4.5 hours. Actually amazing he did this so quickly, given he had never seen a PT before...and also took the hyd pumps out with the engine, so all those hoses were removed as well.

Related post: http://www.tractorbynet.com/forums/p...tting-out.html

[BobRip]

I just had a problem with my year 2000 PT 422 running on only one cylinder after running for about two hours. I pulled back the shroud on the front of the engine and noticed a thick (1/8 inch) coating of oil and grass on the inside. I power washed as much as reasonable and then reassembled. It ran ok for about two hours and then started to run on one cylinder. I checked the output of the ignition coil by taking off the little rubber boot on the coil wire at the spark plug and then using a screwdriver (held well back on the plastic handle) I grounded the terminal. I could see then that the engine sound did not change when I grounded the terminal. Sometimes there was a little spark and sometimes none. I ordered a coil from Continental Engines. After replacing the coil and setting the gap between the coil laminations and the rotor it ran fine. The gap range was 0.012 to 0.020 of an inch. I used two 0.016 inch thick feeler gauges, one at each end of the coil. I have tried with one before and could not get a consistent gap from end to end. The new coil is narrower than the old, so I had to over tighten the bolts. I recommend putting three extra washers on the bolts to make up for the narrower coil. I was suspicious of this coil and checked with Subaru and it is the correct coil. The engine runs fine now, but I have not done a two hour test yet.

[BobRip]

Oh, I did some more cleaning prior to final reassembly. I partially removed the metal shield around one cylinder and used compressed air. A lot of trash came out. This may have been blocking or reducing air flow. I will now be cleaning this out every two years or so. This was the left cylinder. The right seemed ok, with very little trash. I have about 1000 hours on the engine and 700 hours on these coils. It is possible that the trash caused the coil to overheat and fail.

[BobRip]

Oh, I did some more cleaning prior to final reassembly. I partially removed the metal shield around one cylinder and used compressed air. A lot of trash came out. This may have been blocking or reducing air flow. I will now be cleaning this out every two years or so. This was the left cylinder. The right seemed ok, with very little trash. I have about 1000 hours on the engine and 700 hours on these coils. It is possible that the trash caused the coil to overheat and fail.

Given the trash that I found in the engine, has anyone tried putting screen or something else over the expanded metal sides and front to block grass, dirt, etc. I expect it would have to be cleaned out at least after every mowing, but it would be easier to clean than the engine.