How does your Dolmar/Makita oil?

[deutzman]

Don't remember off the top of my head what brand of chain oil I use but I buy in 5 gal. pails and use the winter oil(they offer summer or winter blend) for winter use here in Va. My 7900's both use a tank of oil per tank of gas. The winter oil is thinner than anything I've used in the past but is still sticky and stringy.

 

[gmax]

As Andy has said 32" bars are about max for the 6400-7900's and I've owned 3 of them.
One of my 7900's did start losing oil flow over time and 1000's of trees and a very simple trick fixed it (thanks to Wayne or gmax on AS).
All I did was tip the oil out and replace it with mineral turps and ran the saw for a bit without a bar. The crap that came out was nearly black and after a while clean turps started flowing. Haven't had an issue since
This may not work in your case but is certainly worth a shot.

Actually it was kero not turps

 

[Streblerm]

What brand bar oil & what temp. at time of use?

Stihl, tractor supply brand and some pretty thin winter stuff from the local hardware store. None of them made much difference.

I am only running a 20" bar on the saw and it still isn't oiling enough. As it stands I wouldn't go any longer. The longest bar the saw would ever have on it is probably a 24". Any longer than that and I run the 394.

 

[Streblerm]

The oil lines are new and I cleaned the strainer when I replaced them. If I lightly pressurize the tank then lots of clean bar oil comes out the pump inlet line.

 

[makguy]

Have you removed the oil pump from the saw and inspected it? With heavy use the plastic gear within the pump that rides against the pump drive can get stiff and cause a low oil issue. In a few cases I have seen the plastic gear within the pump melt solid and the pump would not turn at all. Replacing the fitting in the rebuild kit wont do anything for you if the drive gear doesn't move nice and easy.
I would also check:
the ends of the pump drive and make sure that they are not melted or distorted.

The oil lines are free of debris

The hole in the bar lines up with the oil outlet properly, and is not full of debris.

Is the vent free of debris

You are using the correct weight of oil for your area, in the south we use summer blend all year long.

With the maximum adjustment on the pump you should have plenty of oil for a 30 inch bar without burning it up. Otherwise I would say you have an issue with your oiling system

 

[Andyshine77]

I don't know of of any plastic gear inside the pump, other than the adjustment screw that act as a limiter.

In this pic you can see the adjustment screw, the knob or cam at the end can wear down with use or abuse. I suspect that's the cause of your problems.

How does the pump drive look? Part #038 245 030. If the ends are broken off, which I've seen before the saw won't oil at all. The clutch drum drives this part and needs to be aligned with the drive, if not you can break the ends off.

 

[Sabertooth]

My Dolmar oils how ever I like. I adjust the oiler to full, because its easier on the bar ect.

A gas tank to an oil tank is what i live by.

 

[MCW]

Actually it was kero not turps

Tasted like turps?

 

[gmax]

Tasted like turps?

Much like Pod coffee!.....I owe you that one...

 

[Streblerm]

I don't know of of any plastic gear inside the pump, other than the adjustment screw that act as a limiter.

In this pic you can see the adjustment screw, the knob or cam at the end can wear down with use or abuse. I suspect that's the cause of your problems.

How does the pump drive look? Part #038 245 030. If the ends are broken off, which I've seen before the saw won't oil at all. The clutch drum drives this part and needs to be aligned with the drive, if not you can break the ends off.

I removed the pump limiter/adjuster cam and it looked just like your pic. Just for kicks I modified it as outlined in this thread: http://www.arboristsite.com/chainsaw/156738.htm and it made no difference in the pump's operation. The pump drive also looks good.

It sounds like most people don't really have complaints about oil delivery so I am going to inspect the check valve operation and if it seems ok then I am leaning toward worn pump. Like I said, it oils some but not enough for a 20" bar.

 

[Andyshine77]

I removed the pump limiter/adjuster cam and it looked just like your pic. Just for kicks I modified it as outlined in this thread: http://www.arboristsite.com/chainsaw/156738.htm and it made no difference in the pump's operation. The pump drive also looks good.



It sounds like most people don't really have complaints about oil delivery so I am going to inspect the check valve operation and if it seems ok then I am leaning toward worn pump. Like I said, it oils some but not enough for a 20" bar.

Well I don't know, if the pump is fine could be something simple. Maybe the line in the tank is kinked.

 

[Streblerm]

Well I don't know, if the pump is fine could be something simple. Maybe the line in the tank is kinked.

I'm thinking the bore of the oil pump is worn. I had a similar problem with a well used 034. Same process. Replace line, still not enough oil. Replace pump, all is good. It may have to do with what POs were using for bar oil.

 

[Streblerm]

I think I found the problem:msp_biggrin: I ran the saw with the bar and chain installed but without the clutch cover so I could see what was going on. It oiled like a champ. The clutch cover was packed with oil soaked fines and I believe that wasn't allowing the check valve to "breathe". I cleaned the clutch cover and now I am getting a nice line of sling off from the bar. I also shortened my modified nub on the limiter so the pump has more throw. Time will tell if this was a good move or not. I'll just have to see if the tank of oil lasts through a tank of fuel.

Now on to the next problem. I was having erratic tuning issues and intermittent shutting down. I chased that down to a broken spring on the choke shaft. It was allowing the choke to partially or even fully close. This has been going on for quite some time as the choke shaft is severely worn. I can't believe it was running as well as it did with the choke partially closed most of the time. I can't wait to get it back together with a fully functional carburetor.

 

[acbell]

I have a similar problem with my 5100 which has recently stopped oiling. Where is the vent for the oil so that I can check it? Also, do I need a special tool to remove the clutch assembly? My Stihl takes a standard 19mm, but I don't see any wrench fitting on this Dolmar clutch.

 

[RobShelton]

I have a HD 6401 that has never oiled. In fact I got so fed up with it I just shelved it for years. I cleaned the tank vent, checked and changed the lines and pump before realizing the pump drive (worm gear) isn't even touching the other gear. Actually someone had been in there and moved the pump assembly over toward the pump drive in an effort to get them together. Anybody heard of something like this?

I suppose I should not have said "Never oiled." If I filled the oil tank on a cold day as the saw warmed up I would get globs of oil off the bar tip. But once warm - no oil. Guess it was expanding and pushing it out.

Anybody have any ideas?

 

[Matt81]

I have never had any issues with any of my Dolmar or Makita saws not oiling properly. They are the most reliable saws i have ever owned. I sometimes wish they oiled a bit more due to the tough dry and at times very dusty wood over here, but a 32" is absolute max for a 7900 anyway really. I rarely use anything over a 28" on the 7900. I have switched to a new brand of bar oil and have been getting noticeably better oiling right away. Much more oil on the chain at bottom of the bar than with the cheaper brand i was buying before. Can't complain about that!

 

[psuiewalsh]

I was messed up for a while. You have to 1/4 turn to the Left! Opposite from my other saws

 

[zogger]

I have a HD 6401 that has never oiled. In fact I got so fed up with it I just shelved it for years. I cleaned the tank vent, checked and changed the lines and pump before realizing the pump drive (worm gear) isn't even touching the other gear. Actually someone had been in there and moved the pump assembly over toward the pump drive in an effort to get them together. Anybody heard of something like this?

I suppose I should not have said "Never oiled." If I filled the oil tank on a cold day as the saw warmed up I would get globs of oil off the bar tip. But once warm - no oil. Guess it was expanding and pushing it out.

Anybody have any ideas?

They are worn down too much to touch each other? If you have a local dealer with new parts, perhaps take in your used parts and compare?

 

[RobShelton]

They are worn down too much to touch each other? If you have a local dealer with new parts, perhaps take in your used parts and compare?

I should have mentioned I tried an oil pump and drive gear from a running, oiling saw and still no oil. I hope to get a chance to look at it again and then I will post on here again. Thanks all!

 

[cheeves]

My HD 6401/7900 conversion doesn't oil worth a crap. When I got it it oiled everything but the bar due to leaking oil lines. I replaced the lines which solved the leaking issue but very little oil is getting to the bar. The limiter screw looked OK http://www.arboristsite.com/chainsaw/168711.htm but I modified it anyway http://www.arboristsite.com/chainsaw/156738.htm with no change in oiling It is using some oil but I can't detect any on the drivers when I pull the chain out of the bar groove. The chain is getting hot and I am detecting wear to the chain/bar after a few tanks as well as some bluing of the bar. I can also see very little "sling off" from the tip of the bar. Yes, the chain is sharp. There is very little difference between my new-ish Carlton bar and the bar that came with the saw so I don't believe it has to do with the bar. If I run the saw with no bar I do get oil at the bar mount but it is kind of hard to judge volume that way.

My thought process is leading me to believe that being run with the leaking oil lines by the POs caused wear in the oil pump leading to sub-par oil delivery. Before I spring for a new oil pump I just thought I'd check with some other 6400 owners. Is this stingy oiling common to these saws or do I have an oil pump problem? Thanks in advance.

You could try drilling out the oil holes in the bar! I did it helped.