Methanol burning 084 rebuild

[mdavlee]

I bet it was straight methanol with the wide squish band and small chamber. Unless thst chamber is way deep it shoukd have plenty of compression

 

[Stihlbro]

At this stage, I am most interested in the fuel and what to use.
The nuts and bolts are easy

You need to find methanol for racing. VP sells it, it may be available locally like at a dirt track. There is a methanol for 4 strokes that has a topend lubricant. Just make sure it is specified for engines, not the hardware store type.
I would completely disassemble the carb and inspect throughly. At least put new soft parts in. Pay particular attention the the needle and seat,spring and fulcrum position. The carb has been reworked to run on methanol or as some call it alcohol. The fuel passages have been enlarged so can flow possible 2 1/2times more than what gas requires. Renew fuel pick up line and if it has a filter, duplicate it the same way you found it.

I would make detail notes of the disassemble with specifics of pop off pressure, and needle settings. The nuts and bolts are the same as any saw. Qualify the kill switch or make sure you have a way to shut the saw down if needed.

 

[mdavlee]

Kill switch sometimes won't work or pulling the plug lead. I've had to hold the decomp and open the butterfly to kill some

 

[Stihlbro]

Squirt bottle with fuel/oil mix is your friend or a rag to choke it out, at least that is what a friend told me.

 

[Adirondackstihl]

@cuttinscott uses his thumb to kill their nitro Dolly. Otherwise it'll runaway.

PS: Scotts thumb has about the same diameter that of a golf ball. Your mileage may vary.

 

[spencerpaving]

Local hobby shop sells some premix fuel for nitro RC cars

https://www.frontlinehobbies.com.au/categories/I/J70

Any preference between KL 200 or benol?

I would start with straight meth...then if you want start adding nitro to see what it likes...you have to pump huge amounts of fuel to start running higher nitro percentages.
..I wouldn't run rc fuel....it has too much oil in it and often too much nitro

 

[spencerpaving]

Kill switch sometimes won't work or pulling the plug lead. I've had to hold the decomp and open the butterfly to kill some

Yes and yes...been there

 

[mdavlee]

I would start with straight meth...then if you want start adding nitro to see what it likes...you have to pump huge amounts of fuel to start running higher nitro percentages.
..I wouldn't run rc fuel....it has too much oil in it and often too much nitro

The RC fuel I have is 20% oil. It run ok but was better with extra methanol. I have some M5 now but I ran out of time messing with the carbs.

 

[spencerpaving]

The RC fuel I have is 20% oil. It run ok but was better with extra methanol. I have some M5 now but I ran out of time messing with the carbs.

I didn't think about cutting it with straight alky...that would work

 

[mdavlee]

I didn't think about cutting it with straight alky...that would work

It was 15% or 30% nitro already.

 

[Brewz]

Thanks for the input folks, keep it going, I'm learning here.
I guess I could always fit up a stock HT and just run petrol but I would love to get it running as it was made to run

I am going to get back in touch with the bloke I bought it off and see if he can remember where he got it

 

[mdavlee]

Thanks for the input folks, keep it going, I'm learning here.
I guess I could always fit up a stock HT and just run petrol but I would love to get it running as it was made to run

I am going to get back in touch with the bloke I bought it off and see if he can remember where he got it

If the pipe was made for methanol it may be shorter than ideal for gas from what I've been studying

 

[Brewz]

I'm thinking I may take the alcy carb off and fit up a regular fuel carb first.
I guess I can check compression and space the head up a touch with a gasket/spacer to get it running on 98 RON fuel

 

[Brewz]

If the pipe was made for methanol it may be shorter than ideal for gas from what I've been studying

Mmmm

 

[mdavlee]

It may be fine on gas. Easy to measure the chamber and get a compression ratio.

 

[Brewz]

Yeah, speaking to a fella well versed in racing here in Aus just now and he recommends I stick with normal fuel.

I am tending to agree

I just don't have the knowledge yet

 

[Deets066]

Yeah, speaking to a fella well versed in racing here in Aus just now and he recommends I stick with normal fuel.

I am tending to agree

I just don't have the knowledge yet

Only one way to gain that knowledge Tony

 

[CR888]

I think if you want to run pump gas the carb would need reworking as it probably has drilled/enlarged jets to deliver the fuel on methanol. Also some advice on methanol from folks who use it will help with maintenance....ie flushing saw after use to keep parts from deterioration. A bit of work goes into a successful conversion to alky, do you want to undo that? I'd try alky first before trying to switch back to pump gas, it would be a wooty hooty saw. Cool project!!

 

[Stihlbro]

I agree, is try alky first.

 

[Brewz]

Well I just had a chat with my local racer friend who knows alcy saws and he has offered to help me get it running on methanol one day if I take a drive to his place a few hours away.

I think I will!

Rebuild is first