Stihl 056 problem

[mcguirejohnson]

I'm new to this and not an expert with saws, but I was given an 056 Magnum by my father in law. He's had an 051 for 35ish years (still has it) and he took this 56 on a trade last year. He was told it had good compression etc. He never ran it and I got it to run pretty quickly over the holiday. He suggested I take it and once I got it to my house I started it and went to use it in the woods. Once it took on a load it started to bogg down and die. The next day I took the bar off and had a really hard time getting it to start. Once it get choked and it starts, It then dies pretty quickly. I checked the compression and it's just under 110. I'm familiar with this process from our dirt bikes (two strokes) and jet ski's (2 strokes as well), but I've never done it on a saw. I held the throttle wide open and pulled the rope as if I was trying to start it. First question is to verifiy that I'm using the correct process for checking compressionon a saw. If so, then I would suspect low compression is the reason for my issues, but I'm not sure what the normal compression range is for one of these saws. I did play with the low and high screw and could not get it to run any better or worse by moving them out/in etc. My father inlaw was told the carb had been gone through (he did the trade with a chain saw shop in NC) and it's really clean, so I don't suspect carb issues.

I appreciate any suggestions.

Thanks,
Jim

 

[GBD]

You don`t have to hold the trottle open at all, as it will pull in air by exhaust port. You do have to pull several times to get a correct read, though.
140-160 psi would be OK.

 

[AVB]

I would still think there is a problem with the carburetor. The fuel filter could have fell or broken off the fuel line allowing trash to migrate to the carburetor. Most carburetors has a small screen filter inside them for such a case. Some of the new screens are so tight that it doesn't take much to clog them. Another problem area is the diaphragm; could have either harden or the metering isn't set correctly. All three can cause fuel starvation.

 

[mitch95100]

110 is low pull the muffler and check for scoring. Also if it pops and cracks when under load it could be the timing. My bet is on a burnt piston though

Sent from my USCCADR3305 using Tapatalk 2

 

[scallywag]

Try this first.... seat both adjustment screws on carb, that is screw them all the way in gently, now back the "H" high speed screw off 1, 1/8 turns open and the low speed screw 1 turn open, see if that helps.

 

[mcguirejohnson]

OK...i broke it down today and found a few things that are inline with the above suggestions. Prior to this, I checked the compression again without holding the throttle open and it checked out closer to 125. When I took the carb apart, there was a lot of dirt in the screen. I've cleaned this out, but not put it back together yet.
View attachment 276012View attachment 276013View attachment 276014

I've attached a few pics, but not sure if they came in correctly or not. I'm on the road this week (work), but will put it back together next weekend and see how it runs.
Thanks,
Jim

 

[Mad Professor]

Looks to have been running too rich by ex port goop.

Are those just streaks of carbon, or carbon scores on the piston?

Might want to pull the jug and get all the carbon off the cylinder and piston then put in a set of rings if internals look O.K.

Also does not look like the carb had been serviced/cleaned, it's pretty filthy

 

[nstueve]

1.) check for play in the crank. As unlikly as it might be if you have bad bearings you're probably dead in the water anyway. if you can move the crank on either side of the saw in any direction even slightly you probably have a failing bearing. Bearings might be easy to replace but are like hens teeth to find since they are NLA and aftermarket doesn't make the correct size; same problem with oil seals. This is why you start here so you don't spend a bunch of money and not get it running. Since you've had it running I would suspect everything is ok but you better check to be safe!

2.) feel the piston scoring with a screw driver
a.) if the screw driver hangs up buy a new piston Chainsaw Parts should have one
b.) if the scoring doesn't catch the screw driver buy new rings from above site as they sell caber rings

3.) replace fuel lines

4.) clean carb
a.) if the carb diaphram is stiff just put a new carb kit in. Again northwoods probably has a kit for that...

 

[Braintree]

The clutch side bearing # is 9523-003-4460 is "NLA" The flywheel side #9503-003-0510 is available by a price list I have,but its from 2011.The 045 clutch side bearing will not fit #9523-003-0440.The same is true for the oil seals; Clutch side 9640-003-2690 "NLA" Flywheel side #9633-003-2210 is available.Good luck,these are great saws but parts are hard to find

 

[OREGONLOGGER]

Get a Tilloston RK-HS full kit includes new copper seat don't get a aftermarket kit make sure you get a OEM Tilly kit for the carb. Buy the looks of the carb you posted a kit is needed spend $12.00 on carb kit and install it correct. Low screw at one turn and High screw 1 1/4. 125psi is fine plenty of compression to fire up...good luck

 

[mcguirejohnson]

Get a Tilloston RK-HS full kit includes new copper seat don't get a aftermarket kit make sure you get a OEM Tilly kit for the carb. Buy the looks of the carb you posted a kit is needed spend $12.00 on carb kit and install it correct. Low screw at one turn and High screw 1 1/4. 125psi is fine plenty of compression to fire up...good luck

Thank you for the suggestion. I was looking online and saw two different kits. One is RK-21HS and the other is RK-20HS. Any idea how I can tell which one belongs to my kit?

thanks,
Jim

 

[mcguirejohnson]

I cleaned the carb and put the saw back together and set the High at 1 and the low at 1 1/4 (this is where it was before I took it apart. I tried the recommended turns listed above and it did not run as good as it does now. I have not run it with the bar, but plan to do that within the next few days. Thanks to everyone for their suggestions.

Jim

 

[mcguirejohnson]

I have a follow up question...I cut 3 truck loads of firewood this last weekend and the saw died down towards the end (similar to before) and the carb was caked up again. My air filter seems to be very thin in several places. I've ordered a new one, but wanted to also make sure I'm running the correct oil mixture. After researching on this site, it seems 40:1 is the recommended, but in talking to my father in law, he runs his 051 at 25:1. The reason I ask this is because my exhaust is just spitting out the oil (my jeans were completed black from the exhaust). Another thought is this could mean I need new rings, but I'm not certain. Thanks for any suggestions. Jim

 

[scallywag]

I have a follow up question...I cut 3 truck loads of firewood this last weekend and the saw died down towards the end (similar to before) and the carb was caked up again. My air filter seems to be very thin in several places. I've ordered a new one, but wanted to also make sure I'm running the correct oil mixture. After researching on this site, it seems 40:1 is the recommended, but in talking to my father in law, he runs his 051 at 25:1. The reason I ask this is because my exhaust is just spitting out the oil (my jeans were completed black from the exhaust). Another thought is this could mean I need new rings, but I'm not certain. Thanks for any suggestions. Jim

Jim, I run my 056 on 25:1, it sounds like your saw is still running to rich! does your saw blow a lot blue smoke, even when cutting?

 

[mcguirejohnson]

Jim, I run my 056 on 25:1, it sounds like your saw is still running to rich! does your saw blow a lot blue smoke, even when cutting?

Thats a great question. I know it blows smoke when I first start it, but I did not notice too much when I was running it. The exit port on the exhaust points straight down in the front, so this could be why I did not see much of it. what brand of oil are you running?
Thanks.

 

[scallywag]

Thats a great question. I know it blows smoke when I first start it, but I did not notice too much when I was running it. The exit port on the exhaust points straight down in the front, so this could be why I did not see much of it. what brand of oil are you running?
Thanks.

shell

 

[hotshot]

I have a follow up question...I cut 3 truck loads of firewood this last weekend and the saw died down towards the end (similar to before) and the carb was caked up again. My air filter seems to be very thin in several places. I've ordered a new one, but wanted to also make sure I'm running the correct oil mixture. After researching on this site, it seems 40:1 is the recommended, but in talking to my father in law, he runs his 051 at 25:1. The reason I ask this is because my exhaust is just spitting out the oil (my jeans were completed black from the exhaust). Another thought is this could mean I need new rings, but I'm not certain. Thanks for any suggestions. Jim

40:1 mix is what the owners manual calls for.

The fuel line & outlet sits real low towards the bottom of the tank on an 045/056 saw, and the line could still have a tear in it,
letting the gas bypass the fuel filter at the end, and repeatedly plugging the carb's mesh screen. I assume you put on a new fuel filter or replaced the foam insert, because the old foam replacement type filter degrades over time and re-plugs the mesh screen up fast.

Also, a pressure test will tell you if the heavy layer of carbon in the exhaust port is coming from bar oil, from
the oil tank. The oil tank shares a common gasket with the engine crankcase on that saw (and most others), and
bar oil could be getting sucked over into the crankcase. I'd check the 7-8 crankcase bolts for proper torque too.

A lot of times, you can smell that bar oil burning in the exhaust fumes, smells like the exhaust from an oil refinery
stack and nothing like a 2-cycle boat or weed eater exhaust.

 

[Dan_IN_MN]

Thats a great question. I know it blows smoke when I first start it, but I did not notice too much when I was running it. The exit port on the exhaust points straight down in the front, so this could be why I did not see much of it. what brand of oil are you running?
Thanks.

shell

synthetic? Dino will cause carbon build up. You can run that saw any where from 32:1 - 50:1. The important thing is to run oil. :spam:

 

[scallywag]

Sorry! Shell "synthetic" @ 25:1............. And From the Stihl 045 / 056 work shop manual, 40:1 with Stihl oil........25:1 with "other brand" oil.

 

[mcguirejohnson]

I cleaned out the carb and ran it, but it shut off pretty quickly. Changed the plug (which looked fouled) and it ran. I burned about a half a tank of gas before shutting it down. I did pay attention to the exhaust smoke and it's not blue, but rather it's more of a white color. Does this color give any negative signals?

Thanks,
Jim