3500 problem
I'm hoping this thread is proper place for discussion of my problem.
Somehow very fine wood dust got into fuel and starved my 3500. Unfortunately I ignored the symptoms until it ran out of fuel and refueling I could not restart. That is when I tore down carburetor and discovered the mess inside. Cleaned it up and still no start. Tore it down again and it is full of the same dust. Waiting on kit, I gave it another cleaning and flushed fuel system. I checked the fuel filter and it seems good so I have to wonder how this really fine stuff got past it but plugged screen in carb?
The old diaphragm looked pretty stretched out and possibly tiny leak so I put in the new kit. Still no start luck, but at least I got fuel to plug. Spark looked good, but a new plug gave a brighter blue spark. Bewildered as to why it won't fire up, I noticed it did not seem to have as much compression as previous to that last tank of fuel. Tore jug off and found ring seized into piston with mild scarring on it and jug.
Well that is certainly bad news.
I see where there is an earlier post/thread where someone could not find jug for this saw. I have found several listings but they are pricey. And so is the piston because of the way they have parted it out. It does not make sense to me. You can buy ring, piston pin, and keepers separately, but to get the piston you have to buy a kit where it comes connected to the connecting rod including bearing! What gives with this?
Is there some aftermarket way of replacing just what I need?
I have seen one company offers an upper end kit for several saws which includes jug and piston kit, and cheaper than jug alone. I did not see a listing for this 3500, but they apparently do some crossing of parts because some kits were listed as improvements for other saws which basically oversizes displacement, more power.
Has anyone tried this and what was your experience?
Suggestions welcome.
Because the OE jug is not chromed, and scratches not deep, I have managed to get it reasonably smooth to the point I might get by. I employed a method/fix that was an official Grumman fix for aircraft aluminum known as spooning. It involves a tool that is much like the underside of a spoon and working it back and forth to push the gouged metal back into the scratch.
BTW, the problem occurred at the exhaust port side. Besides the lean burn because of debris in fuel, the fact that the exhaust gasket had blown may have been a contributor, causing improper scavenge. The bolt inside the muffler that holds half of the muffler in place had backed out and was inside the muffler, maybe contributing to blown exhaust gasket. Only way you would have known was to give the saw a good shake so the bolt would rattle. And there is some carbon buildup in the upper area of the cylinder, certainly enough to cause detonation of low octane fuel if the compression is high enough.
Also, in the last few days of searching, I've come across an article related to fuel and high performance saws. I don't think this saw would be high performance, but uncertain. It went into detail of fuels moving to alcohol blends and the effect. It said they burn hotter and recommended "using premium fuel only" if alcohol or MTBE was in the fuel. Prior to these newer blends, owner's manuals often stated to use 87 octane only because it starts easier.
What say you all? (I'd rather tug or turn key a bit longer than have a blown engine.)
