pressure washer overheating

[COACHS 14]

My new 18 HP pressure washer, installed in front of enclosed trailer, a month ago has been working great until yesterday (it was 90degrees) and it kept shutting off on me. I have troubled shooted many options, but the only thing I can think of is that it is too hot in the trailer and it is over heating. I have a side door, rear doors and roof vents open, but I think it is still too hot. Any help or suggestion?

[Scott Stone 604]

Make sure you oil is at the proper level. Also, you might want to open up all the doors to get cool air in.

[cleanhoods 43]

Are you talking about the motor or the burner?

Marko

[COACHS 14]

Oil is fine and no the burner is not on. All doors are open. Maybe a gas line clogged??

[COACHS 14]

Are you talking about the motor or the burner?

Marko

The motor keeps shutting off. It will run for a while and start sputtering then shut off.

[Russ Johnson 141]

Honda or vanguard?

[John T 744]

Check to see of there are no gas lines pinched, if the gas is coming from a tank thats away from the engine make sure the cap is OK and if there is a little vent screw cap make sure it allows air in there so when the engine is sucking up the gas there isn't a vacuum build up in there where the gas can't flow freely into the engine.

Also probably not a bad idea to just get a new gas filter which could be the easy fix.

[COACHS 14]

Honda or vanguard?

Kohler 18 hp

[COACHS 14]

Check to see of there are no gas lines pinched, if the gas is coming from a tank thats away from the engine make sure the cap is OK and if there is a little vent screw cap make sure it allows air in there so when the engine is sucking up the gas there isn't a vacuum build up in there where the gas can't flow freely into the engine.

Also probably not a bad idea to just get a new gas filter which could be the easy fix.

No gas line pinches. The gas tank on the skid mount does not seem to have a vent on the cap. Maybe there is a vent somewhere else that I cant see?

[Guy B 70]

Some gas caps are "Self Venting" happens under the cap.

[John T 744]

Some gas caps are "Self Venting" happens under the cap.

Yes I had one like that on my trailer where the cap went and and the tank would get sucked in when the engine was running causing the engine to stall. I also have that red tank on my flatbed now that had that adjustable airflow screw when if you leave it tightened same thing happens and the engine stalls... But both are noticeable when when there are problems because you would see the tank getting sucked in.... Doesn't sound like Coaches problem..

Russ Johnson the residency expert should have a good answer to this because he pretty much seen it all.

[cleanhoods 43]

Sounds like the low oil cut off is killing the motor. But this is a hard thing to figure out without the motor here,lol. But this is my best guess. Check your oil but run her a sec.

Marko

[COACHS 14]

Sounds like the low oil cut off is killing the motor. But this is a hard thing to figure out without the motor here,lol. But this is my best guess. Check your oil but run her a sec.

Marko

This was my theory. How can I confirm that it is a bad low oil mechanism?

[cleanhoods 43]

First run your unit a minute to get the oil moved around..shut down and check it see where your level is,then go from there. Got a John Deere mower with a Kolher and the oil looks good before i start but when i run it a little it shuts off i checked the oil and it was down put oil in it and runs great.Those motors use oil. Start from the easy and work towards the harder stuff,lol.

Marko

Edited May 20, 2012 by cleanhoods

[chrishartje 15]

I had the same problem a few years back with a vangard. Russ told me it was choke pulling out. The spring was broke...

[COACHS 14]

I had the same problem a few years back with a vangard. Russ told me it was choke pulling out. The spring was broke...

This is interesting because I have noticed the choke sliding over - towards the open position - a few times by vibration or something after the engine has been running. It has just moved over 1/4 inch or less towards the open position, but maybe just this little bit of movement is making the engine stall. Is this what was happening on your pw?

[COACHS 14]

I have tried almost everything but my pressure washer keeps shutting off on hot days. Took gas cap off to check for venting..nope..I vented the engine exhaust out of the floor of the trailer and put a fan on the pw...nope...good gas, good oil, no pinches in any lines.

How can I check if it is a low oil sensor or broken choke? This is a 18hp Kohler motor on an Allison pressure washer. The unit is only 3 months old and has shut off on me on hot days since new. Once it shuts off I have to wait for 20 minutes before it will start again.It will run for a little while and then keep doing the same thing for the rest of the day. very annoying!!! I have a warranty on the motor so I should not have to doing any work on it but it is close to impossible for the mechanic to duplicate my problem to see the problem, since is only happens on hot days after running for 4-5 hours. What should I do?

[mick m 19]

To check your low oil sensor, disconnect the wire at the oil filter.[ There should be a spade type fitting there] If it starts up, which it should'nt, it's the sensor. What about the spark plug leads? Are they getting hot at all? But if it's spluttering as you say, I'd lean towards the engine getting starved of feul or it's vapourizing either in the feul line or the carby. No moisture in the tank? Condensation maybe?????

[Russ Johnson 141]

I'm thinking you have an ignition coil breaking down from the heat. Next time it stalls, remove the gun from the hose and see if it will start. It should run on one cylinder with no load.

[COACHS 14]

I will try what you advised. I will report back.

[COACHS 14]

I'm thinking you have an ignition coil breaking down from the heat. Next time it stalls, remove the gun from the hose and see if it will start. It should run on one cylinder with no load.

Russ, I tried what you said and it would not start. It did it again today. I washed for 4 hours worked great and then it the engine started sputtering and it shut off. It wouldnt start for 20 minutes. It ran for 10 minutes and then the same thing would happen again. I would like to take a hammer to it! All trailer doors were open gas cap off and fan blowing on the engine. What now?

[Russ Johnson 141]

Next time it shuts down, pull a spark plug boot, put a screwdriver in it, get the screwdriver close to the engine, and crank it too see if you've got spark.

What kind of tech advice is Espec giving you?

[Rick2 42]

I sounds electrical but I don't think it's heat related. It ran for four hours without a problem then suddenly quit. If a component was failing from heat it would show up much sooner than that, probably within fifteen minutes or so.

Russ is correct, check for a spark the minute the engine dies. Keep an extra plug with you. Check the strength of the spark now while the engine is able to run and then check the spark at the time the engine fails, I'm sure it will be a weak spark. By bet is a ground fault. Something in the magneto is becoming loose and causing a ground. Start with simple things first like disconnecting the ignition switch. Hope that helps a little.

- - - Updated - - -

I sounds electrical but I don't think it's heat related. It ran for four hours without a problem then suddenly quit. If a component was failing from heat it would show up much sooner than that, probably within fifteen minutes or so.

Russ is correct, check for a spark the minute the engine dies. Keep an extra plug with you. Check the strength of the spark now while the engine is able to run and then check the spark at the time the engine fails, I'm sure it will be a weak spark. By bet is a ground fault. Something in the magneto is becoming loose and causing a ground. Start with simple things first like disconnecting the ignition switch. Hope that helps a little.

[COACHS 14]

Next time it shuts down, pull a spark plug boot, put a screwdriver in it, get the screwdriver close to the engine, and crank it too see if you've got spark.

What kind of tech advice is Espec giving you?

John gave me the phone number to the outfit that built the unit for him. I called them and they pretty much said that they were not familiar with the Kohler motor and directed me to Kohler certified shops in my city. I talked to one shop and they said it was going to be very hard to duplicate the problem since it usually takes 4-5 hours of use before it acts up. The shop went through all of the same stuff I have been hearing everywhere, gas cap venting?, is it old gas? etc.

I called Kohler manuf. today and talked to them about it and they said it is either being starved of fuel (vaporlock or something) or no spark. The latter is what you were saying to test. Kohler said to get a spark tester and see if there is a spark after it dies, but your screwdriver instructions are pretty much the same.

Talk about getting the run around... on a $4000 new pressure. If I had hair I would be pulling it out. I will try to test for a spark next time it dies.

[COACHS 14]

Ok. So here is a picture of the fuel line, fuel filter and how it sags. This is how it was built. One thing that Kohler manuf. said today is to have as straight of a fuel line as possible without any dips in the line. As you can see there is quite a dip in the line below the fuel filter before it leads back down to the fuel tank ( that is located at the bottom of the pw skid). Do you think this dip or slack in the fuel line could be a culprit? note: The exhaust pipe that runs downward by the fuel line runs out a hole in the floor of the trailer. When I first had the problem of the unit stalling I thought it was the heat from the exhaust causing a vapor lock in the fuel line so I cut a hole in the floor, had a tube bent and ran it out the floor....but obviously this did not solve the problem.