Thread: Temperamental 2 stroke engines.

Originally Posted by rover-56

No one has mentioned a common problem I have - mud wasp eggs in the muffler outlet.
Still catches me if I forget the rubber bung.
Terry

I wired a little piece of metal flyscreen over the exhaust. That stopped the buggers.

Don.

Air leaks hard fuel lines hard diaphragms especially fuel pump side of carb low carb pop pressure hard or leaking pulse tubes blocked fuel filters and tank breathers InCorrectly set low speed mixture all common issues for hard to start two stoke engines I make great money as a side line fixing these problems for frustrated punters

I've ben using a Victa "toe cutter" mower for 35 years, a Stihl brush cutter for 19 years, a Makita chain saw for 2 years, they all run on a 25:1 mixture as per manual. An Aldi chainsaw that lasted for 7 years till the plastic fuel and oil tubes became detached also ran on a 25:1 mixture. Recently I bought 2 new Aldi chain saws which require a mixture of 40:1. Why ? What would be different on the new engines? .W.
.

Not necessarily new - while my chainsaw runs on 25:1, a small Honda generator I have had since the mid nineties runs on 80:1.

The main reason manufacturers reduce the amount of oil is to reduce the smoke in the exhaust. To some extent this is due to legislation in some places for some uses, but I suspect that it is mostly an attempt by manufacturers to preempt any attempts to ban their engines.

As to the ratio actually required, this will be determined mainly by the detail design of the engine, especially the choice of materials. I would assume that all very high ratios would need to use all roller or ball bearings, for a start.

Originally Posted by B.S.F.

I've ben using a Victa "toe cutter" mower for 35 years, a Stihl brush cutter for 19 years, a Makita chain saw for 2 years, they all run on a 25:1 mixture as per manual. An Aldi chainsaw that lasted for 7 years till the plastic fuel and oil tubes became detached also ran on a 25:1 mixture. Recently I bought 2 new Aldi chain saws which require a mixture of 40:1. Why ? What would be different on the new engines? .W.
.

Absolutely nothing.

But on the topic of temperamental two strokes. I've been building a husky rancher 50 to run methanol with 5%nitro now that's temperamental

Originally Posted by 460cixy

Absolutely nothing.

But on the topic of temperamental two strokes. I've been building a husky rancher 50 to run methanol with 5%nitro now that's temperamental

You might also need a bit of oil in that mix.

DL

Originally Posted by B.S.F.

I was hoping we could keep "Makes" out of this.
.W.

On this forum? RU serious??

I have two Stihl 08S chainsaws from the 70s, a Stihl FS85 brushcutter, a Stihl backpack blower, 3 Honda engined lawn mowers that are all 20 years or more old, one old Victa 18 toecutter, and one Chinese pole saw less than one year old. I would put $1000 on which one of these WON'T start if I go out there tomorrow. I'd even bet that the RR Classic that sulks down the back will start before that @$&* pole saw does, although the Victa might prefer it if I pulled the spark plug out. That's it, no need to clean it or anything, just remove and replace it. Those old things will run with almost zero compression. Just make the fuel around 17.5:1 to pad out the rings.

I have few issues with old fuel. All the Stihl stuff runs 50:1, using synth oil. I always used to believe the 'old fuel' thing, but I'm not sure these days. Modern fuels are pretty sophisticated. That said, I'll drain the tanks if I'm laying them up for the winter, save the ride on. Can't tip it up. You'd think they'd put a tap in, wouldn't you?