Chainsaw temp for carb adjustment / checking

[Paul in the woods]

I've been checking the revs on my little Echo saw, I followed the carb adjustment procedure for bringing the saw up to temp which involves a couple of minutes of switching from idle to full throttle to idle etc. Then checked the max revs which were about 12,000, so under the max revs listed in the user guide of 12,500. So far so good. However, I decided to check them again after using the saw for a bit of logging and noted the max revs were over 12,500 although only by 100rpm.

 

I assume this is to be expected, i.e. after a fair bit of use the revs may well be higher than when a saw is tuned at service?

 

Also would a saw be able to cope better with revving slightly over maximum revs if a good quality 2-stroke oil is used?

[NFG]

Hi,

If the temperature of a gas is lowered, the volume increases proprotionally assuming pressure is constant.

So if your second test was carried out at minus whatever the temperatures are at the moment, then slightly more air is being sucked in which may influence the rpm.

 

Im sure max RPM has a tolerance as does the accuracy of your rpm meter. I would consider using decent quality 2 stroke oil essential with high revving engines.

[spudulike]

It is quite common for a colder saw to not rev out like a warm or hot saw which will rev higher. Just tach the saw once it is at operating temperature!

[Paul in the woods]

Thank you both. It's not that cold here so I don't think it's the weather. It's the first time I've tached a saw so I'm learning what to do.

 

So, tach after following the warm up procedure rather than taching a very hot saw after cutting a ton of logs?

 

The other thing that surprises me is how uneven the revs are but I'm much more used to cars and mowers.

[spudulike]

Just tach it up when it is hot rather than cold - 3 minutes of warm up rather than 30 seconds, cut a bit of wood then do it.

[Paul in the woods]

Thanks Spud, I'll give that a go. Thanks also for the TT-20K recommendation in other threads, you should be on commission.

[spudulike]

Just like recommending good products, use it daily and no issues at all, good product!