I have heard back in the 1950s people took their two stroke mowers back to the manufacturer when the motor seized and said they always used two stroke fuel,so the manufacturers checked the fuel in the tank by slowly heating the fuel in a pot until the fuel evaporated leaving behind the oil and a lot of the time no oil was left behind so no warranty was given.
Probably the quickest and easiest way would be to remove the muffler and look in the port at the condition on the side of the piston and rings for scoring or a seized ring.
Powertorques with compression and starter fluid in the plug hole always fire unless the spark is washed out (eg over fueling) or the coil or module need replacing .(this is assuming the bore,piston , rings and spark plug are in good condition)
Hi Max, spark on this one is very good, I just can't see why it won't give the slightest kick on the starter fluid, not that this is something new, when I can't get a kick from them I just put them in the non starting pile that I may get back to one day. I am more curious than concerned. If I get a motor that will give a flutter on the starter fluid but will not run on the carby then after replacing the top seal and still no go, then I assume the bottom seal is the problem and that motor goes in another pile.
Hi Norm,I have had a lot of coils and modules and they show good spark when the plug is out and the motor is a no go when plug is in then when you replace the module or coil the motor runs fine again,electrical problems can be intermittent works one second and not the next.
You really need a coil load tester to properly test a coil and not a ohm meter.
As Max said many coils and I might add spark plugs will fire out cylinder compression zone but will once the fuel load and compression are in play will not even arc the plug. Briggs uses a very large spark gap (about 0.140) to test magneto coils but the coils still need to be mount to do this. There reg coils testers but I have never needed one as I just use my head when testing a coil on engine that will not fire.
Also as Tyler mention you must have the minimum amount compression that the Powertorques requires the to start. This I don't know about these engines. Here on handheld two cycles that is 100 psi as the mix with oil requires a higher compression than the 65-70 psi that four cycle engines need. You can crank all day on a two cycle here if the compression is below 100 psi and never get a hit even with best of ignition spark. They might hit on starter fluid but I don't use it here.
Howdy AVB, NormK has mentioned in the past the pitiful compression you can get away with in Powertorques and it will still run and cut the lawn. I had a full crank 160 (predecessor to PT) with a regular piston inside an oversize cylinder that you could move the piston crown more than 1mm sideways with your fingers and it still ran. It stalled very easily though.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
I can't remember if I have come across a Powertorque coil that was faulty, don't think I have. The occasional module can fail but not often, full crank modules fail and I think that is partly caused by the fact the module is mounted on the underside of the ignition plate and does not get any airflow over it. When I replace these I fit them on the upper side of the plate so the fan helps cool it. MF I have had a full crank with a spark plug in the decomp hole and I struggled to find where compression was but it started easily and ran fine, and I used it for years like that. Tyler, compression is good and there is no indication of any puff of smoke or hiss indicating the gasket being a problem. AVB the jury is still out regarding how much compression is needed for these to run, this motor was running very well a few weeks ago. The lack of a kick from it with starter fluid above the piston still has me confused but it is something that happens occasionally. I have at least 50 of these motors here that I am going to set up and test when my son comes over from NZ in a few weeks. That way we can use a known coil, module and carby. It will be interesting to see what the results are, at least then I know what can go to the scrap
A squirt of starter fluid this morning and it started first pull, I had already changed the float needle yesterday and it would not start and it would not give a flutter with the starter fluid. The only thing I can think of is it had fuel in the crankcase , but it wasn't giving any indication of that pulling it with the plug out and the plug mas not showing signs of getting wet. Bit of a mystery I was hoping to come up with some answer for
AVB has mentioned he doesn't like the idea of using ether spray to try and wake up any two stroke engine. I believe he means from concerns of momentary lack of lubrication on firing up. I think in most circumstances, there would be enough oil residue to tolerate a small number if strokes before more two stroke oil arrives via the fuel. What's your take Norm? This is not invalidating AVB's concerns. He is likely right, in some circumstances at least.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
MF on my old Enfield Interceptor the only way I have ever been able to start it with starter fluid so much so that over 10 years ago I mounted a can of Start Ya Bastard in the left hand toolbox with a tube going directly into the inlet manifold and I can just press a flap on the top of the toolbox and this injects directly into the inlet. I had a bloke here yesterday with 2 chainsaws he could not start, quick squirt into the plug hole had both running fine within a few minutes, the bloke was amazed, and a bit annoyed because he had driven for 30 mins to get here and he had to drive back through worse traffic. Each to their own but I won't be giving up on using it myself but of course you don't over do it, I only use it to wake a motor up
You can use spray degreaser (non foaming type) or even water dispersing spray like WD 40, but only through the plug hole. The good thing about that is you get the chance to check the spark plug as well as clear the cylinder of any excess fuel. When my Ryan 31cc engined Ryobi weed wacker sat idle for too long, it just wouldn't so much as murmur. Start Ya Bastard got things back to normal and saved me an unnecessary carburettor kit.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
I mounted a can of Start Ya Bastard in the left hand toolbox with a tube going directly into the inlet manifold and I can just press a flap on the top of the toolbox and this injects directly into the inlet.
Lol, I'm surprised more people don't use this simple solution. Pride perhaps?
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
I'm hanging out for it to come on special somewhere again so I can get another half dozen cans. Last time I got them I paid $7 each for the big cans instead of around $16.
Ok so I had a bit of play time this afternoon so I pulled the heads off a number of these PT's that I have tested over the years and marked them as won't start. These are motors that will not give a hint of attempting to fire with starter fluid in the plug hole. So far every motor shows signs of being run on straight fuel with deep scoring of the bore with a small lump of steel at the end of the score. The motors I have checked were showing low compression so this does not surprise me. If I get a chance tomorrow I will see if I can find some of the motors that had reasonable compression and see what I find there.
OK, so today I had a full crank that was running fine earlier this week and then it stopped.. I have checked everything, everything checks out, even with a squirt of starter fluid in the plug hole, not a peep. I have fitted a new module, only thing I have not changed is the coil and I'm wondering if that may be breaking down under compression. In the open the spark looks normal. Tried several plugs, nothing. I pulled the head and barrel off and all looks fine. I have given it a quick hone, (no marks in the bore) and will put a set of rings in it in the morning and see what that does. Things like this bug me because I like to find a cause as to why things won't work.
I have had one with a HT lead that would earth on the cowl/block when the plug was in the engine, but would act fine when testing (I should get one of those spark testers). And I have seen a blocked decomp valve line - but that was a clogged metal nozzle (where the hose connects to the inlet) on a G3 125cc. And sometimes there is just one invisible problem that remains.
I have been trying to fix one of my whipper snippers - turned out that after all the stuffing around, it was a rotten (on the inside only) fuel line that kept clogging everything. Ran good for 5 minutes after that, and then started bogging down again and expired. I was about to take the carby apart and I saw the problem - the bloody diminutive 250mL fuel tank was bone dry after only a half hour of tuning.
What hone do you find good? I was thinking about getting the small engine hone supercheap sells - but wasn't sure if it was much chop.
Hi Tyler, yes it has me puzzled but hopefully I will come up with an answer. As for the hone I use it has 75mm stones so that it can travel across the ports without problem. MF the coil gives a normal spark at first I thought it might be breaking down once the mower warmed up but the next day it made no attempt to fire with starter fluid down the plug hole. To me this is usually an indication it has been straight fueled but the bore on it was near perfect, not a mark on it or the piston
I had a bloke bring around a Powertorque yesterday that I had got running for him a few weeks ago. After a quick test I said I was pretty sure it had been straight fueled and was now junk. He then asked if we put some oil in the petrol now would that fix it. Anyway he now wants another motor fitted so I thought I would start testing the 17 motors I picked up for $40 a couple of months ago as I had no idea what the condition of any of them was. So far I have tested 6 and 4 of them run fine, the other 2 obviously straight fueled. Very happy so far, hopefully I can get a few more tested tomorrow At least then I can put them in the good pile or the parts pile. There is at least 50 that I need to check and the test rig makes it a lot easier to do.
