Need information for old Homelite Chainsaw

[Jeff]

Hi Creia

Guess Jeff posted while I was writing up my next post, however, I'll post it anyway. You never know, someone else might find the information useful.

I know these little puppies inside out and if your son wants to learn about them, I'm here to answer any questions he may have. It sounds like you're having a little trouble with chain oil getting into the engine. With the engine removed from the housings, sitting on the bench with the spark plug towards you, the oil pump is located just behind the carburetor. There are 3 hose fittings on the oil pump, the left most fitting should have a line going to the bar mount, this is the oil delivery line. The middle fitting is an elbow fitting and connects to the oil pickup line in the tank. The right most fitting is the tank pressurization line and connects to the line with the duckbill valve (the Oregon number for the duckbill valve is 07-004).

How the system works. The oil pump diaphragm is located behind the rectangular cover held on with 3 screws on the right side of the crankcase. The oil pump piston is attached to the diaphragm and is held into the pump by a small spring between the cover and diaphragm. The inside of the diaphragm is connected via a port to crankcase pressure/vacuum, crankcase pressure pushes against the diaphragm and moves the piston out. Once the transfer ports open and crankcase pressure is dumped into the cylinder, the spring pushes the piston back in pumping the chain oil. The crankcase only generates enough pressure to overcome the spring when the engine is at full throttle.

The tank pressurization port is also connected to the inside of the diaphragm so is common with the crankcase, this is why the engine will pull chain oil into the crankcase if the lines are crossed. The duckbill valve is a one way check valve letting crankcase pressure into the tank to help push oil into the pump. The duckbill valve is connected to the pressurization line with a short length of sintered bronze tube and there should be a 1/16" to 1/8" gap between the line and the duckbill valve. This allows air pressure in the tank to bleed back through to the crankcase once the saw has been shut off reducing oil leakage. Hope this points you in the right direction. All the best,

Sky

Wow! Thank you very much for the insight on the chain oil system. I am confident that my oil lines are routed correctly but I will double-check. I have yet to inspect the oil pump. Would it be worthwhile to remove the oil pump cover and check the piston/ spring, diaphragm and blow out the three hose fittings?

-Jeff

[bgsengine]

Wow! Thank you very much for the insight on the chain oil system. I am confident that my oil lines are routed correctly but I will double-check. I have yet to inspect the oil pump. Would it be worthwhile to remove the oil pump cover and check the piston/ spring, diaphragm and blow out the three hose fittings?

-Jeff

Try to think of it like surgery - the least invasive method to arrive at a fix is usually the best and most effective.

In other words, unless you know it is broke, don't try to fix it - I'd start with the basics - line routing and the like, make sure lines are not leaking (air or oil) - check oil pickup filter (chainsaws like to get those things plugged with sawdust that falls in when refilling) if it is easy to access - Basically the simple stuff first , the easiest to get to, the quickest to fix if there's an issue, checking everything on the way in until the problem is found.

Short Answer: no, not worth it, unless you have good reason to believe it IS the problem.

[Jeff]

Looks like the duckbill valve (the larger one) can be had from Poulan as part number: 560955001 or 530026119. The other duckbill, Homelite 69451, is considerably smaller and will not work in the side of the fuel or oil tanks. The smaller one is for attaching to the end of the impulse line that goes into the oil tank or it is used inside of the fuel and oil caps. The two aren't interchangeable at all, but it appears as though they don't need to be as the Poulan number looks to be a valid part.

Hi ParkinLube,

The two duckbill valves on this saw show as reference number 40 (side of fuel tank) and reference number 48 (chain oil pressure line). Both share the same Homelite part # 69451. I went on Ebay with that part number and the same orange valves came up on search results. I did remove both duckbills and they're absolutely tiny and easy to lose!

[Jeff]

bgsengine,

Thank you for the info and duly noted!

* Operational picture links of the chain saw are now viewable on page 3, 2nd post down from the top*

[KE4AVB]

Very well kept saw. I just sent one back to the owner that the case was nearly white where had stored setting in sunlight. Also very nice cleanup job Jeff.

The one I have for personal use is used for trimming fruit trees; only has a 12 bar. Easy to operate one handed although it is not recommend for safety sake.

[creia]

Very well kept saw. I just sent one back to the owner that the case was nearly white where had stored setting in sunlight. Also very nice cleanup job Jeff.

The one I have for personal use is used for trimming fruit trees; only has a 12 bar. Easy to operate one handed although it is not recommend for safety sake.

"Very well kept saw."
Yes, you are correct. That saw only had very limited use back in the mid-1980's. I purchased it specifically for a large custom home construction project in Palm Springs, CA (I was a general contractor in a previous career/profession), where it was used to cut very large beams to length before we hoisted them up on a lift for installation in the wall and roof framing. (Sure saved time over trying to cut those beams with an electric reciprocating saw!) I bet that saw never cut more than 50 beams and it was put back in its (red plastic) case and stored in my garage until Jeff (my son) found it. He has actually got it running pretty good now. After draining the oil out of the auto-chain lube tank the smoking cut down significantly. He just needs to diagnose and repair why that chain lube oil is pulling into the combustion chamber. He is very determined, and with the kindness, collective knowledge, and HELP of so many on this forum (yourself included) it is only a matter of time until he figures it out and repairs it.
Much appreciated gents!
Michael

[ParkinLube]

Here is the repair manual link: http://www.parkinlube.com/pdfs/Homelite%20Repair%20Manual%205th%20edition.pdf it is a larger download, but it will have info you may need.

[creia]

Here is the repair manual link: http://www.parkinlube.com/pdfs/Homelite%20Repair%20Manual%205th%20edition.pdf it is a larger download, but it will have info you may need.

Thank you very much- I'll check it out.
Michael