Help Diagnosing Issue

MrLarkins

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Hey folks, I was away for a few days (29th anniversary celebration), but I'm back today. Mowed when I got home and was able to cut the whole 1.1 acres today(93F) without a single problem. Not even a hint of a problem. I haven't done anything since the last time I tried to mow. Go figure.
 

VegetiveSteam

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Hey folks, I was away for a few days (29th anniversary celebration), but I'm back today. Mowed when I got home and was able to cut the whole 1.1 acres today(93F) without a single problem. Not even a hint of a problem. I haven't done anything since the last time I tried to mow. Go figure.
Sometimes it just happens that way. Thanks for the update.
 

TobyU

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Buy a compression tester and a leak down tester. These are necessary first steps to diagnosis engine running issues. Everything is just guessing, seem to be getting off course?? Valve adjustment cold (70 degree ish) compression, warmed up engine. Good luck!!
I can't agree with that.
I have worked on thousands upon thousands of engines and the last time I screwed a compression tester into a lawn mower engine was probably when I was about 12 years old when I first got a compression tester because that was the closest most convenient thing to make the needle go up.

Now I'll leak down tester could be more valuable but actually just using compressed air and blowing into the cylinder with an adapter would be probably better than I leak down tester..
A compression tester is such a moot point on a lot more engine as most of them have acr's etc and you're not going to get anywhere near an accurate reading to tell you anything and in reality they basically either have plenty of compression or they have almost none.
Simply putting your thumb or finger in the hole and pulling the rope or spinning the blade is more than enough to tell you anything you need to know.
It's irrelevant what the actual number is on the meter so I stopped using the compression tester for mowers decades ago..
 

STEVES

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Had a generator with low compression, started ok, but bogged down with load applied. Compression test told story, no need to go any further, like Oh NO must be carburetor. So yes, there is need for basic testing, especially since I have a 'not so smart thumb pressure gauge'! :eek::confused::ROFLMAO: Spin over 500-600 rpm to by pass ACR.
 

TobyU

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Had a generator with low compression, started ok, but bogged down with load applied. Compression test told story, no need to go any further, like Oh NO must be carburetor. So yes, there is need for basic testing, especially since I have a 'not so smart thumb pressure gauge'! :eek::confused::ROFLMAO: Spin over 500-600 rpm to by pass ACR.
That sounds like a lot of work and kind of hard to tell if you're spinning over 500 600 rp.m. or not. You certainly can't use a vibratach for that and the lost all the digital ones I have and have used don't update quickly enough to give you a consistent reading at that low of an RPM and I doubt most of them with the compression from the tester screwed in would even hit that many RPMs but then again I'm also talking about push mowers without electric start that you pull the rope on cuz we all know that the battery powered starter on these little engines but they walk behind mower doesn't spend them anywhere near 500 rpms. It barely spends them enough to start they're so anemic.
I guess I have a very smart phone because my thumb or finger in the hole will tell me everything I need to know about whether it has enough compression to run well or not.
I have done literally thousands of them though so you get a good feel for it.

I guess it's like using a code scanner for a car which is one of the best diagnostic tools available on cars since 96 because it works excellent and tells you exactly where to start.
But I don't need that. If a car has ignition cylinder mess I don't need to plug the scanner in to tell that it has a miss or even tell which cylinder it is. I can simply reach with my fingers and pop off a coil wire or two or injector wire whichever is easiest to cancel out the cylinders until I find the one.
So I see the compression test somewhere to this. But in my case for the lawn mowers it's faster just to see if it blows out the whole hard enough than it is to screw in the tester.
 
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STEVES

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Most on this site looking for help, won't have 'that' feel, price of tester cheaper (usually) than throwing parts at machine. 50 - 60 lbs good considering ACR and under 500rpm. He can always loan to friends & neighbors that may need help. Getting over 500rpm can be done with drill, but, you have to lift off before you let go of trigger, or most time nut will come off! This takes some experience. Leak down tester is for more experienced person, different ways to lock crankshaft so as not to get hurt, or remove rockers. But cylinders wear more at the top for checking ring leakage. Valves or head gasket doesn't matter as much. We all have our way! :)
 

TobyU

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Most on this site looking for help, won't have 'that' feel, price of tester cheaper (usually) than throwing parts at machine. 50 - 60 lbs good considering ACR and under 500rpm. He can always loan to friends & neighbors that may need help. Getting over 500rpm can be done with drill, but, you have to lift off before you let go of trigger, or most time nut will come off! This takes some experience. Leak down tester is for more experienced person, different ways to lock crankshaft so as not to get hurt, or remove rockers. But cylinders wear more at the top for checking ring leakage. Valves or head gasket doesn't matter as much. We all have our way! :)
Well, if someone doesn't have the feel for compression blowing out of the hole in their finger they certainly aren't going to have the ability to remove the shroud and adapt it with a drill chuck and an adapter to fit a socket so they can spend one over and as I said from the beginning it's just more work than most people need to deal with or that's even necessary.

I have guided pure novices and homeowners through that basic test over the phone many times.
It's not an experienced or educated feel that someone needs.
It's simply the fact that it blows your finger out of the hole when someone else pulls the rope or when they crank the engine over if it's a starter on a rider.
In fact, sometimes it's just a matter of seeing if the piston is going up and down.
Just had one the day before yesterday or maybe it was yesterday call me about a twin that he knew was low on oil and it made some sort of noise and now won't run but it does still spin over without any noticeable noise.
For the first basic diagnosis, the actual amount of compression is quite irrelevant but rather seeing that it has anything from both pistons moving up and down is what's important.

Also, with the finger test regardless of the pressure I explained to people how it should blow blow blow blow blow.
It should be very rhythmic and in a pattern and never have like double blow and then a space and then double blow and it should never try to suck your finger into the hole.

These two tell you you have valve issues, normally with one not opening.
Or, if you have not enough pressure to even blow your finger out of the hole you could have a valve staying completely open like a popped valve seat etc.

All of this can easily be diagnosed but ever actually knowing whether or not you have good full compression or only 85% compression.
I use percentages because again it's kind of irrelevant what the actual number is on the compression tester but more important what it normally is on decent running engines on that same compression tester.
I just hate to see people go out some number and often when people use a compression tester they're expecting at least 100 if not 120 to 150 like on a car.
So when they don't get that because of the acrs they often start thinking of other things that are damaged or tearing into things and causing other problems and expense when all of that was perfectly fine and it was something else to begin with but their numeric number on a compression tester led them down the wrong path because they didn't really understand the situation.
It's fine if someone has done lots of engines and expects to only see 70 on the compression tester but the average person dabbling into this or auto mechanic will not come to this conclusion quickly.

You're right, everyone has their own methods and ways and I somehow once I started doing this morphed and evolved into the absolute most efficient, minimalist way to do everything and then get on to the next one.
Not in a reduced quality sort of way either because my shops reputation for quality work and doing little extra for people speaks for itself and all of the reviews.
I just seem to find all the little tricks and ways to do things quickly and efficiently even if it is a little bit harder for the short period of time I'm doing the work.

You can take a row of other people and myself and present us all with an identical situation mower and say get it running or fix it whatever.

You might find me hanging from a harness from the ceiling basically standing on my head with a head spotlight on and a mirror etc but I would be done in a short number of minutes.
Everyone else would probably have just barely disassembled something and have it over on there very convenient and easy to work on workbench going through something and then they would have to go back and reassemble it all taking 35 to 50 minutes etc when I was done in 9.
I will admit speed isn't everything and it's not good at sacrifices quality but that's not the case with me.
I just choose to work a little harder for a shorter period of time.
Time is of the essence in two situations that I can think of in this regard.
When you have a whole lot more to get to after you finish the one you're on or when you actually work very little so when you do get around to working you have to get a lot done for every minute you work. Lol
 
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