Disston carb problems

[McC]

The coil and condenser gave new life to the ignition of my Disston 101. It throws a healthy blue spark on my spark tester, even while turning the engine at slow speed. I cleaned the entire fuel system, but I don't have any new parts for the Stromberg SC 9/16 carburetor. It dumping way too much fuel into the engine, and fuel is pumping through the secondary Bendix pump into the gear box. Does anybody know where I can get parts for the Stromberg carb and the Bendix pump/regulator?

 

[HomeDelight Man]

Hello, Did you clean out the carb? There maybe a piece of dirt or rag in the main needle seat. This happened to me once. The main needle was stuck open and would dump way to much gas. It also sounds like you may need the seals for your secondary pumper. Good Luck, Jonathan

 

[Lewis Brander]

Fuel Meter Problems.

Scott. did you try the "O" rings I described under my thread for the Disston fuel pump repair kit? It seemed to work for me, Lewis.

 

[McC]

I'll have to look for those o-rings around here, but won't be able to install them for quite some time. I've got too many other things going right now. Thanks for the tip.
Scott

 

[Lewis Brander]

Hope the "O" rings work for you.

When and if you get the time, try the O rings. I feel that they will work. So far I have not seen any gas in my gearcase. I sure hope It works for you. Looks like you replaced the magneto coil on you saw. Did you ever take any ohm meter reading of the replacement coil? My coil throws a nice spark at .025" plug gap, but when I widen the gap, no spark. The manuel says it should jump a 1/4" gap. Was thinking of taking the old coil and having it rewound at a plce near here that rewinds or rebuilds electric motors. Just have to call them and see if they can do it. I would like to know what people are getting for resistance readings across the primary and secondary windings on the coils. Lewis.

 

[McC]

After I put the new coil in, it would jump a 1/4" spark tester easily. I posted the link to Grubb's marine on the other thread, they have all the parts to fix this ign.
Scott

 

[Lewis Brander]

Thanks for the reply

Scott, thanks for the reply. Will check out the site you mentioned. I received an email from a friend of mine and he stated that he's seen plugs that would fire, out of the engine, and not fire in them. The plugs looked great, if fact they were new. but the engine had been flooded and for some reason the engine would not fire untill the plugs were replaced. Guess I'll get a couple spare plugs and try them. The plug in the saw is new but has been soaked quite a few times. Let you know what happens. Lewis.

 

[Lewis Brander]

Replaced the Plug.

Replaced the plug, mixed up a fresh batch of 16 to 1 gas-oil mix and tried to fire up the saw. Not a putt. I even put a teaspoon through the spark plug hole and still not a putt. Looks like time for a new coil. Sent an email to Grubbs to see if they had a set of points. Waiting for a reply. If they do I'll order a coil, condencer and points for the old Disston. Thanks again for the link I'll let you know what happens if and when I get the parts ordered and on the saw. Lewis.

 

[Lewis Brander]

Checked out Grubb's on Old Mercs.

Well, they have the coil and condencer, but no contacts or points. Got an email from the cscolletor and he said that over a period of time the old coils detereorate and if I got a coil and concencer and could not get the points that I might try an electronic triggering device to replace the points. I think I'll order the coil and condencer and stay with the points. Trying to keep the saw as original as possible. So far have not gotten a putt out of her. Did you have any problems with removing the laminated core from the old coil and putting it into the new one? Have not had the coil out of the magneto to see what problems I might run into. Will have to get some time and tear her down again, to see what I might run into. Hopefully get the time in the next few days. Lewis.

 

[McC]

Lewis, I don't recall any difficulties replacing the coil. I think there was a sqaure post or something the coil slides over or through. The conections for the spark plug wire were not a modern connection, you use dielectric grease to seal the connection, but it produces a heck of a spark when you get a good secondary coil in there. Every secondary coil from the scintilla ign I've seen has had the outside cover cracked and falling off. Must not be a good plastic.
Scott

 

[Lewis Brander]

Scott. Thanks for the reply.

Hi, Scott, Thanks for the reply. When I order the coil I'll order the tube of sealer they have also. I'll probably order everything tomorrow and will work on the saw once I get the parts. Thanks again, Lewis.

 

[Lewis Brander]

Hi Scott. Ordered the parts.

Well I completly disasembled the magneto. When I remove the coil, I found that where the spark plug wire attached to the coil was badly corroded and that the coil was badly cracked and deteriorated. It looked as if the corrosion had gotten down inside the coil. I ordered the parts from Grubbs last friday hopefully the parts will be here by wednesday this week. I removed the laminated bar form the old coil. Think I'll use a hot glue gun to install the new coil on the laminated bar so that it's not vibrating or is loose and possibly rub through and ruin the new coil. I also found the model and serial number of the magneto. Will send that to Grubbs and see if they have any record of it and see if they might find a set of contacts for it. Will let you know what happens. Talk to you later, take care. Lewis.

 

[Lewis Brander]

Hi Scott, Got the parts.

Hey, got the parts this morning and after digging up some bulbs and some other work around the house, I got a chance to work on the old saw. Got the parts installed all went OK, except that one of the leads on the coil wasn't long enough and had to lengthen it. After doing that, I got the saw back togerher and now she'll throw a 1/4" spark just turning the flywheel by hand. Found she would do that before I put the recoil back on. At least now the old girl might start. I'll fill her up and see what she'll do tomorrow. At least now the saw should at least fire up. Talk to you tomorrow. Lewis. Thanks again for your help.

 

[cbfarmall]

Lewis:

Can't wait to hear how the saw turns out. Your threads have been very interesting, and I may have even picked up some knowledge to put to good use.

Chris B.

 

[Lewis Brander]

Hi, cbfarmall.

Hi, god ot hear from you again. If I can help anyone I will. Don't have much experience on saws, but am learning. I like puttering on the old equipment and trying to get it to run. Only hope the old Disston will start and run with a few more loving touches. The old fuel meter looks pretty good, but time will tell. Will let everyone know what she does tomorrow. Lewis.

 

[Lewis Brander]

An update.

I thought the ocassion warrented a new thread. The old saw started and ran. Details under, Hi, everyone. an update. Old Disston Saw.

 

[Lewis Brander]

Hi, Scott.

Hi, Scott. I changed the fuel/oil mix from 16:1 to 32:1 using the same 30w Quakerstate oil. The old Disston seems to run better on this mix. Idles a lot better. but I find if you let her idle for too long and then speed or rev her up, she will smoke like crazy. Seems to load up a bit, but after a few seconds, she revs up and seem to run pretty good. I believe that the high speed side could be leaned down some more but when I do that the saw will not idle as long or smooth. I'm going to try and lean down the high speed a bit and when she idles move the run/start lever up one notch to see if it will idle better. Then rev her up and see what she will do. I think what wil end up happening is that I'll have to move the run/start lever one notch to idle, and ued the run/start lever to controol the mixture while the saw is cutting or under load. I don't have anything around here at present to cut or try the saw on to see how it will actually run under load. For now the fuel is drained and am getting ready at some point in time to prep the saw for paint. I contacted Robert Shapton to see if he might have any idea where engine decals might be obtained. No reply as yet. Talk to you later. Lewis.

 

[McC]

Sounds like it's running pretty good for a 50 year old saw. The crank seals must be good if it will idle like that. I run modern 50 to 1 2-stroke oils at 40 or 32 to 1, usually closer to 40. I haven't had any trouble in 20 years of running antique and vintage snowmobiles. Please folks, don't turn this into a big oil discussion.

 

[Lewis Brander]

Hi, Scott.

Most of my 2 cycle equipment calls for 32:1 or 40:1 mix, except for my 2 chainsaws. I've been running the Poulan at 32:1 with no puoblems and the old Disston seems to run well at that mix. If I get the Mobil MX2T oil I'll probably mix up a batch of 40:1 and stick with that. I can't believe the Disston. At 32:1 mix she still smokes like crazy. Have not had her under a load as yet, but for the time I have ran it, it doesn't seem to get that heated up. I've reved her up, idled it and you still could almost put your hand on the cylinder fins and muffler. Doesn't seem to get that hot. Will be a totally different story under load, I imagine. For now I've drained the fuel and am disassembling enough to reclean and paint up the old beast. Hopefully the orange paint I bought will match the paint I left on the old handle. Talk to you later, Lewis

 

[Lewis Brander]

Hi, Scott.

Under my thread, of pictures of the Disston saw I explained that I was disassembling and painting the saw. Finally got her done. Took some pictures, of hew, while doing the paint job. As soon as the pictures are developed I'll post a couple of them. Take care. Lewis.

The pictures were poster on 10/04/03.