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More chain saw problems


GregH's Avatar
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02-09-01, 08:17 AM   #1  
My Jonsereds 801 saw after running fine in the morning, became difficult to start after lunch.
After playing with the mixture screws I was able to get it to run, but you have to throttle the choke and it won't idle.
Any idea what the starting point for the mixture screws should be and what I should do to correct my problem?

GregH

 
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02-09-01, 01:50 PM   #2  
Hi:Greg

The first thing you need to check is the fuel and air filters. It's either one of these items got restricted or clogged up based on the fact that the machine ran fine prior within the same day.

Next item is the spark plug. Two cycles EAT plugs. Possible there just isn't enough spark energy from the plug to fire a leaner mixture.

You may need to open the low speed screw beyond 3/4. Maybe to one full turn initially. Turn the high speed screw open to 2 full turns initially.

The idea here is to get the machine running first even if it runs overly rich. Keep in mind that the low speed fuel circuit also feeds the high speed.

Therefore, keep the low speed setting just slightly rich to avoid an engine stumble when accelerating between idle and full throttle.

High speed has to be set slightly rich also. The fuel oil mix not only lubes the engine, it also helps it cool since the incoming fuel is much cooler then the hot running engine.

A rich high end speed fuel mix in the cyclinder also is the means by which the engine speed is governed. High speed running at too lean a mixture for too long will cause problems you care not to have happen.

Regarding basic carb settings, at sea level, it's 3/4 open for the low <L> speed approz. and 1 1/4--1 1/2 turns open for the high speed approz. These basic settings are just estimates based on altitudes.

You'll need to make the final adjustments once the engine is running at both high and low speeds.


Regards and Good Luck.
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GregH's Avatar
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02-09-01, 07:13 PM   #3  
Sounds like solid advice and I'll be into it tomorrow.

Thanks!

GregH

 
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02-12-01, 12:19 PM   #4  
Update

Tom_Bartco:
The adjustments suggested did not help, so I went further and took apart the carb and checked the in-tank filter.
What I found was a filter that was coated in tar and paint flakes. The "just serviced" saw that my friend sold me last year indeed had been serviced. The repair tag that was on the saw when I got it from him, was dated 1992. He had sworn off wood burning, had the saw serviced and stuck it on the shelf.
Saw runs just like new.

Thanks!

GregH



 
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