Governor on saw carb

[daemon2525]

I am working on a project saw that has a tillotson carb on it.

THe thing has a governor. I am not sure whether I am adjusting it correctly as most of my saws are newer and rev higher.

This saw runs stong, but almost sounds like it has a "MISS". It may be running perfect and I would not know any better. It just does not sound right to me. I have a kit for it, I guess that I throw that at it next.


How does the governor affect the adjusting of a saw?

 

[romeo]

Like my Grandpa used to say, "governors were made to be broken".

 

[Lakeside53]

It just richens up the mixture, a lot... based on vibration from the saw. The limiting action is not and issue when you are cutting - only when you rev it up with no load.

 

[rmihalek]

Gypo posted a picture of a governor with some red gasket cement smeared over it. He said that the purpose of the red stuff was to defeat the governor. I also have an old tilly carb with a similar looking brass screw on it and I was wondering what the effect would be of plugging up the gov with gasket cement?

 

[Lakeside53]

You will glue up your carb if you do that... the gasket cement will certainly dissolve over time. I've see the valve-end soldered shut, and with the red locite-like stuff (as on Gypo's carb).

Assuming you are not just building a "race saw".

Be careful defeating the governor on these old saws.. they are not supposed to rev high and develop their max torque relatively low. When you are cutting in the wood, the governor is a non-issue, and it's is there to stop the saw from coming to pieces.

If you defeat the governor and use the H screw to set the MAX RPM, the saw will be too rich. Leaning out the H for correct mixture will lead to an over speed situation very quickly (how many can always keep a saw that wants to hit 13k+ down to say 10.5k?).

 

[daemon2525]

I put a kit in the carb, but have yet to put the saw back together again.
The neighbor wants to paint the thing.

It just sounds so different than my other saws that I don't know if it is running correctly or not. I will see what it sounds like when I get it back together with the new carb parts.

It almost sounds more like my 5hp briggs on the go cart than my ms260.

 

[Scooterbum]

Just curious,what model saw is it?

 

[Lakeside53]

I put a kit in the carb, but have yet to put the saw back together again.
The neighbor wants to paint the thing.

It just sounds so different than my other saws that I don't know if it is running correctly or not. I will see what it sounds like when I get it back together with the new carb parts.

It almost sounds more like my 5hp briggs on the go cart than my ms260.

Yep... same problem on the concrete cut-off saws - inportant to limit the RPM so the blade doesn't come apart. They may sound rough when you're not loaded, but they sing just fine in the cut.

 

[daemon2525]

Scooter,

It is the Poulan 5200 Countervibe that I have been posting about.

http://www.acresinternet.com/cscc.n...c8b4625939cf439e88256bfa0018f9ce?OpenDocument

I'll post pictures when I am finished. Mine will never look like the one in the picture. It was quite rough when I got it. Hardly ANY paint, it had been dumped out of the truck or a tree fell on it or something.

Funny, I painted it dark green because I could not find lime green paint.
Anyway, my neighbor (who I do almost every project with), decided that it HAD to be lime green, so he is repainting it. The lime green paint that he found it even MORE pathetic than the original color. It should be a hoot to look at when we are done!! :hmm3grin2orange:

 

[PES+]

Can you post a pick of the gov?

I had a few of those saws years back and I don't remember a gov on the carb.

The ignition timing was rather lame on those saws

 

[PES+]

If it has the big brass screw under the adjustment needles it is governed I don't know about that one particular one as I probably had older versions on that poulan. Is that one a plastic crankcase bottom?

 

[PES+]

Self correction

That vintage saw used a compensator carb. All references to governor in this aspect a technically incorrect. Gypo logger ran into what happens if someone decides to block off the compensator...sure you can rev higher but you run into a lean situation mid range and when the engine loads. As I stated when I first when I first found this site I was away from this tuff for a few years and bashing around in industrial electronic controls and automation so the terminology used on the street today sometimes confuses me.

The compensator carbs designed purpose was to allow a window of automatic jetting control to compensate for filter blockage, air density etc. The idea for it was actually developed in karting using a duck bill in the carb on Mac 101s

 

[daemon2525]

I do not know if the thing has a plastic crankcase or not. I think not, as It seems as though the reed valve assembly was screwed into metal.

The governor (as I am calling it) is part number 33 on page 3 of this pdf.
(If anyone really cares)

http://odref.com/poulan/pdf/poulan/gas-saws/5200.pdf

thanks

 

[PES+]

Do you happen to know the year of that one? that is quite different than the ones I had though basically the same layout. I will ask Tillitson whether the valve was used as a compensator or a governor on that application do you have any other numbers on the carb body?

 

[PES+]

I was confused and mistaken

That carb does indeed have a governor which richens the mixture by vacuum or more accurately stated lack of vacuum that allows extra fuel to be added to the mixture. This would sound like more of a gradual drop and burble than a high speed miss. What you are describing sounds like an old rev limit on a coil

 

[daemon2525]

I just looked and the carb only says

HS176A810

 

[daemon2525]

Well to be honest I am not very good at describing what it sounds like.
It just sounds like something is limiting the revs. That is OK with me. I am just concerned that I tune the thing correctly so that I have it running the best that I can without ruining it.

 

[PES+]

That's the number I needed

The 810 so I can see if I can get a circuit diagram. The gov won't fight you all that much tuning just do not go too far off of the suggested starting point on the hi speed needle always adjust and then check acceleration to see when you are getting too lean on the hi end as if you just hold it open tweaking the hi speed needle, the gov will kick in and the rpms will kind of slowly drop......then when you let it back to idle and then open the throttle again, it will die because of not enough hi jet fuel flow ........you'll see when you adjust it. Don't forget to check your reeds and seal the reed block plates well. Leaky reeds will make yah nuts