How critical is a tacho when tuning?

[karl1991]

Hi all, just muffler modded my ms193t and have tuned carb according but I haven't got a tacho. Engine does rev higher than before, but plug color is slightly black/brown. It hasnt been worked yet. Have a slight slight bog on spool up but when I change L it dies on tick over. The bog is over in a millisecond- seems to be the best setting I can get. Do I need to get a tacho or keep an eye on the plug after running it through some rings? Thanks

[Adamam]

I think it's generally considered 'safest' to tune relative to '4-stroking' rather than tacho, particularly once the saw is modded. Who knows what the exact, optimum figure of a modded saw is going to be?

[karl1991]

My understanding of four stroking is limited, I'm on Google atm 😁 I was just worried about the maximum rpm as it revs higher than before, not sure how close to maximum recommended rpm the standard setting was. Should be rather safe with a slightly black plug though? It's half light brown, half soot black, but like I said it hasn't been ran flat out much or buried in timber.

[spudulike]

A tach takes the guesswork out of tuning carbs. If the saw is modded, it allows you to tune the saw and measure the rpm that works best so it can be reset in the future.

I wouldn't be without one!

[Adamam]

My understanding of four stroking is limited, I'm on Google atm 😁 I was just worried about the maximum rpm as it revs higher than before, not sure how close to maximum recommended rpm the standard setting was. Should be rather safe with a slightly black plug though? It's half light brown, half soot black, but like I said it hasn't been ran flat out much or buried in timber.

 

There's loads of 4-stroking stuff on the net, including (somewhere) a thing with audio files as demonstration.

 

Ultimately it's sort of the 'brrrrrrrrr' sounds as opposed to a scream/whine at higher revs.

 

Sawtooth/square wave (hahahah) as opposed to sine wave in vague audio terms. Or a blasting trombone as opposed to a recorder.

 

Spud is right about a tach being handy (I use one all the time) but it isn't very handy at your current point where you don't yet know optimum rpm. All a tach would tell you is the current rpm, not if it's optimum. Different story for factory settings, obviously.

[karl1991]

I've just been on a website that explains it spot on. Maybe the website you are on about, as it has audio clips of rich/lean and the 4 stroking. I will give it a go tomorrow using the guide and audio clips. The mod has already improved the saw even when I cut a small branch with a richer mix earlier. Why is the 193 so restricted?

[Stubby]

Why is the 193 so restricted?

 

 

Because of the EU ........Oh thats another thread !

[spudulike]

Because of the EU ........Oh thats another thread !

 

Think you mean the EPA but it has been rumoured that if we stay in the EU, all broken saws will suddenly start working again:sneaky2: Better than your dangly bits falling off if we vote to come out........at least that is what I was told:001_rolleyes:

[karl1991]

[ame]

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Anyone's opinions of how it sounds? Running abit rich?

[karl1991]

Plug after running through some rings