Husky 61 not reaching max revs

[J D]

Hi guys, I'm looking for some collective knowledge from the hive mind.
I have a friends anniversary edition husky 61 that is under powered & won't reach full revs. Saw has good compression & behaves fine otherwise. Adjusting the hi side varies the rpm as usual but only upto around 10k (no load WOT). This is wound in a bit from the base setting, & winding in further starts to drop rpm.
Carb has had a good clean 2x over (in the ultrasonic as well) & a kit with no change. I was thinking maybe timing but key is in place & everything lines up as it should compared to another 61. I've replaced both coil modules with known good ones & no change.
I know others have worked on this saw before & given these came out both closed & open port I'm wondering if a mismatched cylinder & piston could be the issue... or is there other stuff I should be checking before pulling the top end off?

 

[Cantdog]

Have you checked the spark screen in the muffler? When these clog up with carbon and will cause the saw to act like you describe.

 

[SimonHS]

Found this old thread that suggests some things to try.

https://www.arboristsite.com/threads/husky-61-9-5k-rpm-maximum.354726/
Try all the simple things first - i.e. does the trigger move the throttle linkage through its full arc of movement? New plug? Fresh mix?

 

[HiOctane]

If you run mismatched cyl/piston,be sure if you got closed ports cylinder,you need an open windowed piston.

 

[J D]

Found this old thread that suggests some things to try.

https://www.arboristsite.com/threads/husky-61-9-5k-rpm-maximum.354726/
Try all the simple things first - i.e. does the trigger move the throttle linkage through its full arc of movement? New plug? Fresh mix?

Thanks, I actually made several of the posts in that thread, then ironically got a basket case saw with the same issue myself.
I will revive that to see if there was an outcome though thanks.
I'll need to double check the throttle linkage but otherwise, plug is new, mix is fresh, muffler doesn't have a screen... I'm leaning towards a mismatched piston/cylinder

 

[Cantdog]

Thanks, I actually made several of the posts in that thread, then ironically got a basket case saw with the same issue myself.
I will revive that to see if there was an outcome though thanks.
I'll need to double check the throttle linkage but otherwise, plug is new, mix is fresh, muffler doesn't have a screen... I'm leaning towards a mismatched piston/cylinder

Ok no screen in the muffler, the next easy thing to check is the passage between the final fuel filter in the carb and the inlet needle valve. Pull the screen and the diaphram and just take a look see through the passage and see if there is an obstruction there. I am assuming you have pulled the screen in the couple trips into the carb....this is another choke point for fuel. Another thing to try is with the "H" needle removed and the carb in your hand with the choke open insert the red straw on a can of WD 40 or similar and give it a squirt to see if it flys out of the High orifice in good volume. Do the same to the "L" holding the throttle open so you can see both the idle jet on the cyl side and the secondary jet on the other side of the throttle plate at idle setting......fluid should come out both jets in good quantity. Remember the "L" side trims (adds fuel) to the "H" side at full throttle so if there is obstruction here this can impeed fuel delivery too causing lower rpm. This is all the easy stuff before you look and see if you have a mis-matched P&C.

 

[ballisticdoughnut]

I think pulling the top end would be a good idea just to confirm you don’t have a open transfer piston in a closed port cylinder. This will definitely cause the saw to run poorly, I’ve heard of it happening but never seen it personally. Seems like you’ve covered everything else that could cause a problem.

 

[irhunter]

I think pulling the top end would be a good idea just to confirm you don’t have a open transfer piston in a closed port cylinder.

+1

But, before I did that, I'd measure the compression. If it is any less than ideal, for a few bucks, you can change out the ring(s) while you are in there...assuming you have the correct piston.

Roy

 

[Bob Hedgecutter]

JD- we live in a Nation where guys earn $25 per hour and flat out refuse to pay someone close to $100 per hour to fix their stuff. A Nation where it is our birth right to assume we know all things mechanical and can DIY anything needed and if it does not work out- there is always online sales to dispose of the evidence.

You don't get much easier saws to do a piston reveal on, heck you can leave the muffler and intake tract on to do it- see if things are mismatched with a Terry special piston in there, resplendent with long ear soft wrist pin retaining clips anywhere but 6 or 12 o'clock.

Is the carb even the correct for model carb? You would be amazed what some people can pull out of a box of parts and make fit in order to make things go again- may not go right- but it goes!
Is the throttle linkage from plastic arm to carb plate the correct one to allow full travel of the throttle plate?
You are good enough to cover the basics- start thinking outside the assumed correctness- assume some other hack has been in there and botched or cobbled something up.

 

[Bob Hedgecutter]

I purchased a Hyway 272xp pop-up piston and cylinder kit (black friday sale) for a white top 61 project. I also purchased a Hyway 272 pop-up piston only , for a 272xp saw project. I am confused that the open port cylinder kit came with the non-windowed piston on the left.
The windowed piston on the right was sold individually as a pop-up 272 piston. I haven't contacted the seller because I wasn't sure if piston difference was good or bad. I haven't installed either part yet. Advice ?
Erik.

advice?
Start your own post on the more specific 272 problem?

 

[eb20]

will do, sorry.
Erik

 

[J D]

Thanks for defending my post @Bob Hedgecutter
@eb20 I see you’ve made your own post, hopefully you get the information you need.
I've been flat tac the last few days, hoping to get back into the 61 asap but that might not be for another few days

 

[J D]

JD- we live in a Nation where guys earn $25 per hour and flat out refuse to pay someone close to $100 per hour to fix their stuff. A Nation where it is our birth right to assume we know all things mechanical and can DIY anything needed and if it does not work out- there is always online sales to dispose of the evidence.

You don't get much easier saws to do a piston reveal on, heck you can leave the muffler and intake tract on to do it- see if things are mismatched with a Terry special piston in there, resplendent with long ear soft wrist pin retaining clips anywhere but 6 or 12 o'clock.

Is the carb even the correct for model carb? You would be amazed what some people can pull out of a box of parts and make fit in order to make things go again- may not go right- but it goes!
Is the throttle linkage from plastic arm to carb plate the correct one to allow full travel of the throttle plate?
You are good enough to cover the basics- start thinking outside the assumed correctness- assume some other hack has been in there and botched or cobbled something up.

Thanks Bob,
Yeah I'm generally one of those guys although I like to think I put the time & effort into doing stuff right (but I guess the "Terry" you refer to probably does too).
I'm sure I checked the linkages & that the butterfly was opening fully but its been a while so I will confirm that. I also know I'm definitely not the first person to have at this thing (& believe it or not the last person to was actually named Terry!) So I will bear your advice in mind next time I go over it