Running fine, engine stopped running and blade free-wheeled to a stop. No compression and piston not moving with pull rope. What do you think happened. Thanks
#2
dfbroxy
I would venture to guess a broke piston rod.....And that a engine teardown is in order. Please post what you find.
#3
AnthemBassMan
Definitely sounds like the connecting rod snapped. Easiest way to see is pull the carb/reed mounting plate and check the crank from that end.
Removed the carb and saw a quarter size hole in the block. Guess it's a parts mower now. What a disappointment, its the best of the three I have.
Thanks for the responses .
Frank
#5
AnthemBassMan
Ouch! Yeah, that will do it! Well you could either make money off it parting it out, or you could find a good engine cheap.
Correct! For years I was in the camp of using only air cooled 2 stroke oil because I never had a manual. But low and behold, it’s right there straight from Lawn Boy that if you don’t use the LB oil, you are to use a TWC-3 that is certified by the NMMA. LB engines turn at a slower RPM and use forced air cooling. They don’t run anywhere near the RPMs or temps that chainsaws, trimmers, or blowers do. While I don’t use LB oil, I do use a TWC-3 rated Pennzoil 2 stroke oil with a little Sta-Bil 360 Marine formula added to combat the ethanol.
L8R,
Matt
#11
tom3
New info for me too. Just got my mower and using Husq. oil mix at 40;1. Thanks for the info, I'll get it right real quick.
#12
LB7268
I used mag 1 air cooled oil in my 10550 and the engine coasted to a stop. Ended up being the ring stuck and scored the piston. I rebuilt the engine and use tcw3 only. I also opened up the pilot jet. Been running great for 8 years since rebuild.
Exactly! Just get whatever brand you can find that shows it's an NMMA certified TWC-3 oil. I've always been a Pennzoil fan, but as long as it's on that list, you can get the cheapest one you can find. My local Walmart also has a 1 gallon jug of Pennzoil XLF Marine 2 stroke oil that's made for older engines for $17.94. An excellent price when you consider the prices added up of either the single mix bottles, pints, or even quarts.
People forget that back when the mowers were made the mix was motor oil in a fuel can and shake till your eyeballs rolled around in their sockets all by themselves.
However now days we have modern 2 stroke oils that disperse all by themselves, burn without smoke or ash and lubricate 500 times better than car engine oil.
Thus the mix can become a lot thinner.
This has the advantage of adding more fuel.
Less oil = more fuel on every stroke and as the fuel is thinner it is easier for the carb to lift and vapourises a lot better.
In most cass you can nearly 1/2 the oil and your mower will run so much better.
The local 2 strokes down here ran 25:1 on BP Energol
I run them on 50:1 with Stens 2 stroke and have been doing so for a long while with very good results.
With Victas it is easy to check because they run a 1/2 crank so it is only a 10 minute job to pull the starter off and check what sort of oil has accumulated in the lower ball bearings and what wear pattern you are getting on the bore.
#17
Teds
I think it's important in any discussion to define the terms and talk about the same things to avoid misunderstanding. By that I mean for example when someone suggests gas oil mix ratios of 50-1 or 100-1 we're definitely not talking about the LawnBoy oil in the green can. Don't do this.
Sometimes, people will talk about running "lean" when referring to 50-1 or 100-1 gas oil ratios. This is incorrect. Gas and oil mix ratios in different proportion do change the air fuel ratio, but not the way people often think. More oil means a leaner air fuel ratio by definition. Regardless of the mix ratio it is important to adjust the carburetor for (relatively) clean burning. This is important and it is usually ignored or at best misunderstood. The manuals will usually say something like "1.5 turns out", this is the starting point, so it will run, and not the end point. It will be extremely rich. The altitude needle as it was called is actually a precision adjustment and the correct set point varies depending on temperature, and gas oil mix ratio. Jetting also plays a role. What I've seen in the past is that a typical 2 stroke mower received indifferent maintenance or tuning, was fed a heavy diet of oil in the gas (a little "extra" must be good too, right?) and a mistuned carburetor - will exhibit lots of smoke, fouled plugs, heavy sludge in the muffler and eventually through long use, stuck rings and scored cylinder walls.
I purchased a "Krylon Rebuild" mower that exhibited all these features, and more. The needle bearings were just about done for, and it was fortunate that I rebuilt it when I did as I suspect it would not have made it through another season without a failure.
This makes 3 seasons on the rebuilt engine, this winter I'll pull the jug and take some pics and we'll see what a steady diet of 100-1 of a modern high tech oil does. I will say the classic LB muffler sludge is much improved, and importantly the exhaust ports stay cleaner.
Check Ebay for a dura force short block, 100 or so, I did that 5 years ago with my dura force,
#19
tom3
Picked up a case of Lawn Boy 2-cycle engine oil. With stabilizer. No other specs at all. Mixes 16 to 64:1 Product of USA. #89930 for 8 oz. Sure hope it's not some ultra low emission stuff that sucks as a lubricant like the SN spec. motor oil. Guess I'll find out over time.
