Older lawnboy mix ratio with MX2T?

[bob555]

Ok, my 85+ year old grandmother religiously mows her yard with a pair of ~20 year old LawnBoys (she had a new one for about a week, then traded it back as she hated the kill switch, safety skirt, and starter rope location). She's probably mowing ~2 acres, and she really works at it, probably mowning twice a week for at least six months a year.

Anyway, according to the Lawn Boy literature, you're supposed to mix LawnBoy's own oil at 32:1 and all other oils at 16:1. She threw a rod running Homelite oil at 32:1, so she's scared of running anything but the lawnboy oil now. Then, a couple of weeks ago, she had yet another lowerend failure (different mower). I think the 16:1 mix that she's running now is causing major hard starting and whatnot, and would like to get back to 32:1, but not spending my summer rebuilding her engines.

So, my thought is to run MX2T, but I'm not sure what ratio to use? I'm thinking 32:1? Any advice on gas brand? I'm thinking that it might help to avoid the ethanol gas?

 

[cryptokid]

well, when she threw a rod, does this mean the rod broke in half or does it mean one of the end bearings seized up and broke the end of the rod off?

 

[bob555]

Big end bearing seized, and tore the cap apart. No damage to the crank, or the rest of the mower. The other failure was the bottom crankshaft bearing. I think over the last ~50 years, she's had two or three cylinders and pistons replaced for scoring/seizing.

I should be specific that I don't think that this is a design defect on the mowers, as she's owned Lawn Boys since 1949, and they have all given at least 15-20 years of pretty heavy service. If I had to guess, she puts close to 30 hours a week on them for most of the summer.

When I say them...lol...she rolls two of them out, primes them both, turns the ignitions on, and gives the first one three little baby tugs. If it doesn't start, she pulls on the second one three times. She then goes back and forth until one of them starts. When that one runs out of gas, she lets it cool while she mows with the other one, if it starts easy that is. Probably 75% of the mowing is actually done with one mower, because it happens to start a fuzz easier.


Even more than she hates the newer models with safety features, she hates self-propelled mowers: they're too heavy to push when they run out of gas, and they move slower than she pushes a regular mower!

 

[cousincletus]

I don't like self propelled either. Too heavy and awkward for mowing around stuff and mowing drainage ditches, etc. I have been using Amsoil 100:1 oil in my Lawnboys (for 5 years now), but at a richer mixture. Amsoil recommends mixing one 8 ounce bottle with 6 gallons of gas to get the 100:1 ratio and I mix one bottle with 41/2 to 5 gallons of gas. Works very well with no carbon buildup or scoring/wear on the cylinder wall. Checked the cylinder last year (you can remove the muffler and look through the exhaust port) and it still had the machined look to it. Compression was still 120.

 

[Blue99]

MX2T at 32:1 is a good choice for Lawnboys.

The lawnboy green can oil smokes bad enough with a 32:1 ratio. Running at 16:1 is probably eliminating all the mosquitoes plus any small dogs & stray cats in the neighborhood.

Bearing failures can also be caused by chunks of carbon deposits or dust ingested thru the carburetor.

 

[blano]

Big end rod failures in two strokes is moet times either caused by lack of lube or dirt ingestion.