What's the most recent reed valve saw that was made?

[ackack]

Thanks, Mike. I was wrong about the key; it is separate. But it in good shape and is lined up correctly in the flywheel slot.

Regarding your thought on delivering fuel, that's what I thought might be the problem and the reason I joined this thread on reed valves. I thought maybe the reed wasn't opening. But as I said earlier, I was able to push it open with light pressure. Plus, when I put a little fuel directly into the carb bore to prime it, the fuel sits in the carb until I pull the cord lightly and then it disappears. I assume that the pulling action is enough to open the reed sufficiently and cause the fuel to travel into the cylinder ... as it should. So, fuel seems to be flowing ok, it has spark, exhaust is clear ... but no go. Maybe it is a compression issue even though the piston looks ok and I get decent resistance when pulling the starter rope. I've had this happen only once before where a backpack seemed to have starter rope resistance but I later discovered a scored piston and cylinder.

 

[ackack]

Still messing with this 1800. I think I have fixed the carb/reed valve issues (but not 100% sure) because I was able to start it the other day & run it for a minute or two. Then I cut it off to see if it would start again ... nope. Flooded maybe? So, I removed the spark plug & saw that the gap had been mashed closed. Had to be from the piston. Regapped & tried again. Same thing. The plug that is in the saw is a Champion CJ8Y; the manual calls for a CJ8. I don't have a CJ8 to compare length... is the CJ8 shorter than the CJ8Y? And here's a puzzler ... why would the saw have run for awhile & then quit? If the CJ8Y is too long, wouldn't the piston have smacked into it on the first stroke?

 

[OldJack]

I don't have a Champion chart handy, but I recall that a -Y plug has extended electrodes which is why it got bashed. Later, Found a cross-reference chart.You need a CJ8 or a RCJ8 if that's the correct heat range. The Bosch WSR 6 F and NGK BPMR 7A are popular chainsaw plugs for recent saws and are the correct configuration, but many be a bit cold.
http://www.sparkplug-crossreference.com/

 

[ackack]

Thanks Jack. Now I know; the "Y" means projected, no letter means non-projected. I knew that "R" on the front end of the plug # meant resistor but never paid enough attention to the back letter when there was one. This saw came to me from a friend who laid it up for years because he couldn't get it started ... guess why!! I checked the plug for carbon and wear, and tested it for spark ... all good. I merely supposed that he had the right plug and moved on to other issues like rotted fuel lines, dirty carb, etc, all of which I serviced. Likely the original owner bought the wrong plug which is an easy mistake to make since the letters are so similar. Will get an CJ8 or equivalent non-projected plug in the next few days and report back.

 

[ackack]

The 1800 is running great. It pays sometimes to read the manual. The key for starting this saw (and perhaps similarly for all tools with no purge bulb) is to hold the handle with the right hand with the throttle trigger depressed while pulling the rope with the left hand. Most "modern" 2 strokes do not call for depressing the trigger so when I couldn't start this old Poulan previously it was because I didn't do so. But then again virtually all newer machines have purge bulbs to assist in the starting effort. I since have noticed that the choke lever on many carbs nowadays also has a mechanism on the far end that slightly opens the buttterfly whenever the lever is moved tho the choke position (see picture). So, it is not necessary for the starting instructions using this type of carb to insist on having the user depress the trigger. Still, this doesn't apply to those carbs that utilize a simple plastic piece (like on many Echo products) that is often attached to the air filter housing and simply is slid over the carb bore to effect the choke. I suppose that, if a purge bulb is present, it doesn't really matter whether or not the butterfly is opened. Anyone care to weigh in?

BTW, just a rough estimate on the newer equipment carbs with which I have tinkered: about half have the choke built in and half not.

 

[Bret4207]

Purge/primer bulbs went out in the late 60's and only recently have I sen them making a come back on lower grade consumer level saws. I don't believe I own any saws that don't have a throttle lock that have been made in the last 40 years. Common practice, as far as I know, is to lock the trigger open, activate the choke, pull until it coughs, shut choke and pull again at which point the saw should start. There may be saws that start with the throttle closed, but I don't think I've ever owned one, other than maybe my 116si Sachs which is the best starting saw I've ever seen.

 

[ackack]

I should have been more specific. I wasn't referring just to chainsaws when I made my last post but also to other 2-stokes, like blowers & weedeaters. All of the latter seem to have purge bulbs nowadays. In any case, I just wanted to pass along my experience with getting an elderly, non-purge bulb chainsaw going after it sat for many years; opening the throttle a bit was the clincher.