8N Noob with oil pressure problem (among others)

[green_achers in MS]

Hello, everyone, first post here. I have an 8N with side-mounted distributor, but indeterminate vintage. It has been one problem after another since I bought it, to the point that we have named it "Art" for "Yard Art", which is about all it's been good for. I so far had to take it to a repair shop for a crack in the block and a worn governor. Now I am having trouble getting it to idle right and maintaining oil pressure. Here's the symptoms:

Once started and warmed so I can let got of the choke, it will have an oil-pressure reading of about 20. After as little as a half hour, it will be down to about 10. Yesterday I got one of the longest work sessions out of it, but the pressure was down to 0 after about 3 hours.

It also starts out running pretty smoothly, but after a while gets really ragged. I see a bit of dark smoke at the exhaust and at the oil filler and engine oil dipstick. I am still just figuring out the controls, and the throttle has me pretty confused. At the middle point of the arc, it will be very slowly idling or as it heats up, it will shut down. I don't have a tach on this tractor, so I can't give the RPMs. On the lower quadrant, it just dies. I haven't figured out what this quadrant is for. The tractor seems to run best near the top of the upper quadrant. However, if I try to set it all the way open, it bounces back to about 90%.

I fooled around with the carburetor screw on top, which I am guessing is the main jet adjustor. It got a lot of the roughness out at idle, but I still have to keep the throttle pretty open. I can see a smaller screw on the lever connecting the cable from the governor to the carb. I'm guessing this is the idle, but don't know how to adjust it. Should I try to adjust it so that the lower quadrant gives me a low idle, or is this sector for something different?

I am also concerned that the problem might be in the fuel line to the carb. I do see rust in the resevoir almost every time I check, and I have flushed out the carb and lines once. It seemed to help a little, but not enough to know if this is the problem. Should I drain the tank and clean it out? Also, I can't figure out how to get to the filter inside the tank.

What are the chances that the oil pressure problem is related to the throttle/carb problem?

As you can probably tell, I'm pretty inept mechanically. I am almosty as old as this tractor, so I can remember carburetors and distributors at least well enough to have some theoretical knowledge. But it's been a long time since I turned a wrench on anything like this.

 

[Bruce (VA)]

First off, your oil pressure problems & carb problems are not related.

As to oil, try increasing the weight. Pick the weight of the oil by the condition of the engine (oil pressure) & the outside temperature. Many folks use 30w detergent all year. A worn engine with multi-vis oil may lose it's oil pump prime if it sets a while. Many use 10w30 or 40. Some like the newer diesel rated oil because of the additives for the flat tappets. (I'm not convinced that my 2400 rpm N engine needs the same oil as my 65 Mustang did) Anyway, IMHO, use a detergent oil. Increase the weight if the engine has low oil pressure. If it gets infrequent use, stick w/ straight weight.

Your carb is probably waaay out of adjustment. Nobody gives a better tutorial on N carbs than Dell (WA). This is from Dell; I followed his suggestions on all three of my N's, which idle at 400 rpm:

"Heres the deal, much to the dismay of gov't smog bureacrats, every carb and engine needs indivual carb ajdustment. Thats why theres them handy-dandy carb tweek'ems.

Both Ford and Marvel/Schebler say to set both the side-pointing idlemix and the down-pointing mainjet to 1-turn as a starting point. I set the down-pointing mainjet to 1-1/2 turns and LEAVITT!!!

Then adjust the side-pointing idlemix for FASTEST idle; NOT SMOOTHEST idle. Understand? FASTEST idle. Then adjust the behind the carb idle-speed set-screw for SLOOOooow 400-rpms idle. Do that idlemix adjust for maximum idle at least 3-times.

Remember the side-pointing idlemix is BASSACKWARDS; out for lean, IN for ENRICH. Mine usually end up about 1/4-turn. Yours may be different.

As as side-note; one of the founding N-Board members used to claim 80% of all carb problems were found in the ignition system. Something to think about.........Dell, yer self-appointed sparkie-meister "

Now, regarding the lack of throttle response, that is a classic case of a governor problem. But, get the carb adjusted first, then post back.

You might finds these tips helpful; # 45 will help you w/ the sediment bowl, & I highly recommend you follow the advice in tip # 39:

http://www.ytmag.com/articles/artint268.htm

 

[green_achers in MS]

Thanks for the help, Bruce. I have been thinking I should put in a higher weight oil. I changed the oil not long after getting the tractor, and just went with the recommended 30 wt. We've been having 100 degree days around here lately, and I'm pretty sure this tractor counts as "well worn."

But I am such a mechanical idiot, I'm not sure what Dell means about turns on the carb controls. From which position do I start counting turns? It appears that I will need to set the idle screw with the engine off. Am I right about that?

I can also see I'm really going to wish I had a tach. Do you know how hard it is to install one? There doesn't appear to have ever been one on this machine.

 

[gahorN]

I got a couple of cases of SAE 50 wt aviation oil donated to me by the local oil distributor. (Old cardboard cans of MobilOil Red-Band non detergent.) I add a couple quarts of straight detergent SAE 50 to it, and that's what my 9N has run on for the last couple years. (I resleeved it with new pistons/rings/rod-bearings but left the old main bearings in there, which didn't do a lot for my oil pressure...so I decided to use the SAE 50 oil.) Guess what? Summer and winter.....(Texas)...Does just fine.
Got about 35 psi when cold and about 20 when hot.
I work 'er hard, all day long, in the Texas heat, bushoggin the grass runway, pastures, etc., and she's happy as a lark. When she's really hot, she idles at 10 psi. So what? Oil pressure is oil pressure. 5 psi would be OK, because that's all it would take to keep it lubricated.
Straight weight oils is good for N-Ford tractors and most other plain, cast-iron engines. Multi-grades may be good for modern import cars but I'm still runnin' my '92 Jeep Cherokee with SAE 30 wt, cheap brand, and at 305,000 miles I plan on continuin' runnin' it.

 

[Dell (WA)]

Greenie........why do you gitt confused about counting turns??? There is ONLY 1-WAY to count turns; from full turning screw IN until it stops (be gentle) and then count the UN-SCREW TURNS-OUT from stop. Simple, eh?

Thats right, only the later 8N's have a dashmounted "proof-meter" tachometer.

RPMS ain't too critical, but iff'n yer sphincterly challenged, you can buy transistorized watch battery operated, LCD display tachometers from outfits like JCWhitney, NortherTools, local landscaping lawnmower shops, that are multi-cylinder selectable and are fired off of one of yer sparkie wires. Sticky them to your dashpanel. Simple, eh?........respectfully, Dell, yer self-appointed sparkie-meister

 

[green_achers in MS]

Thanks for the clarification, Dell. I am mentally challenged by this if not the other thing, which some might say is the same thing...

The problem I'm having with adjusting the idle is that the tractor will now only stay cranked at full throttle. As soon as I try to back it off a little, it dies. A friend advised me to try disengaging the governor and try to control it by hand as I set the idle. He also wonders if the problem might be in the pointz or sparkies.

 

[green_achers in MS]

Thanks. Another oil change is definitely in my near
future...