Leak down vs Compression test, Pressure Washer

[zenoahphobic]

I've done a search on the internet and it seems a low oil switch cuts the ignition.
My last look sometime ago, I don't remember anything like that on the engine, but this was never on my mind.
Problem is the whole machine is totally drenched in dust ( the wife mows dust too!). So dusty one is very tempted to hose it down. I don't think an air compressor is going to be good enough.
If it did have a low oil switch it may be faulty as oil half on checker on dipstick , although ready for oil change (100 hrs?) but it has been a year or two.

[TownsendsFJR1300]

My 13 Hp Honda on my ride-on mower starts fine but after a while and only sometimes shuts down as if there is a thermostat. As positive as day then night. Seems to occur more when my wife uses it. It can't be predicted could go for many hours then shuts off.
Can't find a thing wrong with the bunch of wires and have been assured there is no thermal cutout - I'm not too sure.

That issue is 99% its the magneto coil (next to the flywheel).

I've had one larger engine(over 10 HP) that quit and a weed-eater that would run fine till it got to a certain temp then loose spark. I had to confirm it (as it was super hot) with a slip on timing light connected to a 12 volt battery. No spark once it got that hot. Cooled down 10 minutes, SPARK!!! Replaced the coil, runs fine, all day long-issue gone...

As a side note, on my 8 HP B&S generator, the coil "epoxy inside it" leaked out and locked up the motor (locked the coil to the flywheel-literally!!). Still fired once broke loose, but it was replaced.

At one point I still didn't have spark. Found the "oil level switch" was grounding out the ignition (plenty of oil). Disconnected that wire from the switch (hint, hint Zeno), fired up. Pulled the switch out, pulled it apart (very simply actually), didn't see anything wrong but sprayed contact cleaner at the contacts, re-assembled, works fine..

I have no idea how the Honda oil level switch works, might be sealed but the Briggs came apart easily. But try disconnecting it temporarily to rule it out

[99yam40]

I have an old monkey ward 1700 watt generator with a B&S motor that would run for a little while and then just shut off.
I do not use it much at all, but do change the gas and fire it up every so often.

Finally decided to figure out what was going on.
So I fired it up again and it ran and shut off after just a little time.
I checked for spark which I did by sticking a screw driver into plug wire and holding on to it, got a small shock so put it back on and it started up again then died . Did this several times and then noticed it was a little harder to pull, checked the oil and it did not register.
put oil in it and it now cranks and runs fine without shutting down.
I know there is not an oil switch on that old thing, so thought maybe the piston was just slowing down the motor enough due to over heating without enough oil that it just stopped.
Strange, maybe it was just trying to get me to check the oil. I do not remember draining the oil so maybe I am getting old and forgetful. but i had to put too much oil in it to just be low

[boscoe99]

I have an old monkey ward 1700 watt generator with a B&S motor that would run for a little while and then just shut off.
I do not use it much at all, but do change the gas and fire it up every so often.

You are taking me back in time.

Monkey Ward
Western Auto
Sears Roebuck (now Sears but maybe not for long)
Woolworths five and dime
SH Kress
The Rexview drive in theater

[TownsendsFJR1300]

I remember most of those ^^^ too.


I swapped my neighbors CAT pump onto my good 9 HP Honda PW(after plugging the "idle down" cable hole) this am.

My ORIGINAL pump max is 3,200 PSI, WOT this newer pump, 3,400 PSI, (same wand tip), works great (actually the relief valve seems slightly smoother)!!!

Still waiting to hear from my neighbor..

[zenoahphobic]

That issue is 99% its the magneto coil (next to the flywheel).

I've had one larger engine(over 10 HP) that quit and a weed-eater that would run fine till it got to a certain temp then loose spark. I had to confirm it (as it was super hot) with a slip on timing light connected to a 12 volt battery. No spark once it got that hot. Cooled down 10 minutes, SPARK!!! Replaced the coil, runs fine, all day long-issue gone...

As a side note, on my 8 HP B&S generator, the coil "epoxy inside it" leaked out and locked up the motor (locked the coil to the flywheel-literally!!). Still fired once broke loose, but it was replaced.

At one point I still didn't have spark. Found the "oil level switch" was grounding out the ignition (plenty of oil). Disconnected that wire from the switch (hint, hint Zeno), fired up. Pulled the switch out, pulled it apart (very simply actually), didn't see anything wrong but sprayed contact cleaner at the contacts, re-assembled, works fine..

I have no idea how the Honda oil level switch works, might be sealed but the Briggs came apart easily. But try disconnecting it temporarily to rule it out

Magneto coil ha. That would be under the flywheel. I think the oil level switch is in the crankcase necessitating splitting the case- no thanks I think I would just disconnect it. Would the world stop if I did this? I don't think so as I have never run any engine out of oil. What is the dipstick for- requires no tools, no backbreaking gymnastics to get to. Maybe the existence of the dipstick means this engine has no low oil cutout.
Judging from internet threads these are a pain everywhere. But then again how many people would start a thread about how fantastic their low oil switch is!
The dribbling out of epoxy syndrome. I have seen it once when my LED trailer lights oozed onto the concrete. I put this down to poor manufacture; they must have run out of epoxy on the day and used toffee instead!

[TownsendsFJR1300]

Magneto coil ha. That would be under the flywheel. I think the oil level switch is in the crankcase necessitating splitting the case- no thanks I think I would just disconnect it. Would the world stop if I did this? I don't think so as I have never run any engine out of oil. What is the dipstick for- requires no tools, no backbreaking gymnastics to get to. Maybe the existence of the dipstick means this engine has no low oil cutout.
Judging from internet threads these are a pain everywhere. But then again how many people would start a thread about how fantastic their low oil switch is!
The dribbling out of epoxy syndrome. I have seen it once when my LED trailer lights oozed onto the concrete. I put this down to poor manufacture; they must have run out of epoxy on the day and used toffee instead!

That coil shouldn't be under the flywheel, but just under the main cover. The gap is usually set at .010" BUT simply putting a business card between the flywheel and coil, release the mounting screws and the coil will pull into the flywheel. Tighten the coil, remove the card and gittyap!

And the low oil switch should be accessible from the outside. You'll see ONE wire going to it and likely two bolts holding it in (NO splitting cases). Pull it and expect to loose half your oil (or empty before hand). You can confirm its the correct wire by grounding it while the engine is running and it will kill the engine (thinks its low on oil)..

I check my oil regularly also BUT, I suspect the main reason is for the low oil switch is for generators that run literally WOT for HOURS on end (where more oil would be burned).

Here's a pic of the Yamaha, flywheel and coil, but its the same set up. Its at about the 10:00 position. NOT hard to do at all:

[zenoahphobic]

Townsend you take good pictures (great technology today).
I took the cover/ shroud off (never been off) and yep the infamous all in one magneto ignition on outside between fan and starter ring gear. The lighting or charging coils appear to be in under the flywheel.
No evidence of low oil switch. The lead off this coil goes to a micro switch that was designed as engine off when throttle lever pushed low, but it seems to be positioned out reach and is piggybacked with a wire continuing on to the ignition switch. Although appears OK I might bypass it as it is not used.
It's a very small chance that this is the infrequent culprit.
But that coil with nothing else possible is probably guilty of quitting on the job.
I think by far these single systems spells the death of many a small engine, I shudder when faced with the prospect of replacement these things are either unavailable and costly .
I think I have two weed wackers , a small Honda generator, a handful of chainsaws and probably machines I cannot remember with expired coils!

[TownsendsFJR1300]

Coil failure is pretty rare in the machines but does happen.

**Also, just for S&G's, if you don't know for certain about that micro switch, simply pull the connector off it. That may be the issue. Run it W/O that hooked up, get it hot and see what happens. If it still dies when hot, you know its likely the coil.

If hard to get to, just unplug the wire from the rear of the coil and run W/O it connected to the coil (the ignition cut off switch WON'T WORK). Just use the choke to kill the engine.



Fuel (at least here in the US) is terrible and clogs up jets within a month if not treated and not used.

I just replaced a fuel tank (hairline crack) on a small, cheap blower for my dad. He lets it sits (he won't dump the fuel back in his 5 gallon can and run it dry). I had to clean the carb AGAIN as the fuel (bout 1.5 months old) gooed it up.

At least I got a chance to put the tach on it and tune it another 1,000 RPM's to about 8400 WOT...

[99yam40]

I have never bought a lawn mower, generator,weed wacker, edger,or leaf blower that runs on gas in my entire life.

People just give them to me when they buy new ones because they cannot get the old ones to run any more.

I even give some away after making them run again.

I have not bought a computer for the last 20 years,
Just repair ones given to me.
I take that back I just paid $99 for a Infocus Kangaroo portable computer with Windows 10 on it just to get familiar with something beside XP because I know I will have to switch off of XP very soon

It keeps me busy and working with my hands and brain some times.
Parts are usually not too expensive if you look online

I just fixed a pressure washer with fuel problems for a guy that gave me a Quency 2HP air compressor in return for doing it for him. Jet and bowl was just gummed up.
The 2 HP electric motor just had a bad Start capacitor.
Looking to rewire it for 240V and trying to find out what size start cap is needed when I switch it to 240V.
Waiting on an ELECTRICAL ENGINEER I sent a e mail to to respond back, he has said if he cannot come up with the proper way to size it he knows someone that should.
It is good to have friends that know people

[TownsendsFJR1300]

Found the problem(s).

The plastic gear RPM governor failed (missing two of 3 pieces).

That lead to lower rod to crank failure. The rod had overheated (major discoloring) enough that (I believe loctite) failed and was loose (bolts loosened!!) by approx 1/8".

(BTW, the camshaft does have a compression release on the rear side of it).

Some slight galling:

[99yam40]

Looks like lack of oil.
Not sure the governor would cause lack of oil to crank shaft and bearing

[TownsendsFJR1300]

It had plenty of oil when I got it (seized up-big time). The oil was pretty dirty so I know someone didn't add oil after the fact.

Looking UP the cylinder walls from inside the case (the head is still on), the cylinder looks great. Where the rings run, dunno. Leak down was about 7% at the rings when tested.

And that outer case does have a "low oil" switch inside it.

WOT, RPM's are usually about 3,600. I know if you by-pass-pin the throttle, it'll easily run up to 7,000 RPM's

Something else that may have been an issue. The pressure pump itself, has an "idle down valve"-control cable to the throttle that lowers the idle when the trigger is released.

That valve(at the pump) with cable, was frozen/failed.

I've since pulled the CAT pump and disabled the idle down mechanism. It was tested on my good 9hp Honda PW engine and works great (200 more PSI actually-3400 PSI)

[zenoahphobic]

If we are playing a guessing ****, and from half way around the globe looking at those two pictures it would seem that this was rather a quick failure.
Why, 1. the insides look very clean
2. the heat colour is confined to that local area (big end), and
3. others may have a different view, but, it appears a lot of aluminium has been ripped off (dragged) the bearing cap than the corresponding steel from the journal on the crankshaft. Because a gradual wear failure would show up as a lot of wear on the steel than in the aluminium, all things being equal (that there was sufficient oil). (aluminium retains far greater oil lubricant than steel so it has greater protection against wear, somewhat contrary to the belief that because it is by far the softer metal, that it should wear more.)

However if the bore was also scored (no picture or advice), then clearly the conclusion would be reached that the engine was run without oil.

Townsend can you repair this? throw it away? Or replace rod and cap and crankshaft? Would fix be cost effective, in Australia definitely not?

[TownsendsFJR1300]

However if the bore was also scored (no picture or advice), then clearly the conclusion would be reached that the engine was run without oil.

Townsend can you repair this? throw it away? Or replace rod and cap and crankshaft? Would fix be cost effective, in Australia definitely not?

There was dirty oil in the engine when I got it , so no one added any. Once I got it unfrozen, I put in brand new oil.

When I drained it the other day and pulled the side cover, it was nasty gray and the crankcase was nasty with thick gray goo (I wiped it out CLEAN looking for broken parts). There is obvious heat damage to both the lower rod and crank. The rod bolts actually loosened up leaving about 1/8" gap between the cap and rod.

Looking UP, to the cylinder (the head is still on) looks very clean(cross-hatch marks still there)

Repair wise, a BRAND NEW engine, on is $300(US). The rod alone is about $50, the crankshaft is $207.00.

So no, its not worth fixing. Its getting parted out. (I just sold the pull starter overnight for $60.00 on E-bay ($188 new))

My neighbor gave me the entire unit, CAT pump and all. I tested the pump, works great(200 more PSI than mine), so I have a spare pump (NEW IS $600 alone).

Anyway, the initial thread was about leak down and compression. I guess the
camshaft compression release kept the over all compression low, but the leak down at about 7%...

The head will eventually come off and see if that's damaged, I think the entire block itself is ok as is everything else....