Fouled plugs???

Cooper0809

Cooper0809

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Fergus, Ontario
I have a few questions about tuning and plugs. My oil cable is set at 17.5mm which is really rich I just found. Should be around 20-22mm. Well, I looked at all my plugs yesterday and this proved to be true... I fouled them, they are black, chunky and wet.


Now I've been running this way for the past month or so, is it bad to keep using fouled plugs? And can I just clean off the carbon build up and reuse them?


Here's my next question, for tuning purposes IF the carb settings are spot on should I just be able to adjust the oil pump cable to feed it less oil? Or do I need adjust carb settings somewhere if I adjust oil cable to compensate?
 
you can clean them but it may not run right, personally i would just replace them. for the carb adjustments, if your jetting is spot on(leaned out from factory) you should richen the oil pump a little. this is because you are using less fuel and less throttle to makes x amount of power compared to stock settings. this means the oil pump is not being opened as much, so less oil to the engine for how hard its working. you must compensate for this by adjusting the oil pump settings to feed more oil.
 
So could I just adjust the oil pump up to 20mm to give it less oil? Right now it's at 17.5mm...and then start with a set of new plugs?
 
This is where it gets some one confusing for some folks. Keep in mind the same volume of fuel will be going threw carbs (fuel being gas and oil) By leaning out amount of oil you will be enriching the amount of gas. We need to be aware what ratio gas/oil to then be aware of fuel/air ratio in regards to a rich/lean burn. I would adjust to 20 and keep an eye on it, several plug checks, look threw the plug hole with a pen light and see what the tops of pistons look like. If your plugs arent completely fouled (wont fire) I would clean and re-use for now. Mainly due to a brand new plug is much harder to read accurately. Once your happy with the wash/plugs and are confident motor will live where your at put a new set in.
 
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Cooper0809 said:
So by decreasing the amount of oil, if the plugs still look wet....then I'd need to adjust the fuel screw??
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There is other casual factors as well. Worn/weak reed pedals, weak plug caps or even a weak stator could cause a weaker spark = weaker burn. You need to check them (plugs) in each carb "circuit" 1/4, 1/2, 3/4 and full throttle so to speak.
 
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Refer to the "jetting Hammer style" write up. wet look at idle may be spot on mid and WOT rpms. Adjust as needed per plug readings. Have you kept track of how much oil your using? Rumor has it when the oil pumps go bad they usually drop in to full bore mode. Meaning adjusting oil pump cable wont affect oil consumption. Smoke a lot?
 
Cooper0809 said:
I have a few questions about tuning and plugs. My oil cable is set at 17.5mm which is really rich I just found. Should be around 20-22mm. Well, I looked at all my plugs yesterday and this proved to be true... I fouled them, they are black, chunky and wet.


Now I've been running this way for the past month or so, is it bad to keep using fouled plugs? And can I just clean off the carbon build up and reuse them?


Here's my next question, for tuning purposes IF the carb settings are spot on should I just be able to adjust the oil pump cable to feed it less oil? Or do I need adjust carb settings somewhere if I adjust oil cable to compensate?
Click to expand...


You should get the oil cable adjusted properly then re-evaluate the a/f settings. By reducing the oil delivered you're richening the air/fuel ratio.


Sounds like it's fat with oil anyhow so I would adjust the oil cable to spec, fill and mark the oil tank and also fill the fuel tank. Ride it until the fuel gauge reads empty. Use a qt. bottle of oil and refill the oil tank to the mark you made previously. You should just about empty the qt. bottle of oil when refilling (within an ounce or so).

Now check your plug color/piston wash which I'd guess will be on the rich side. Adjust (or not) accordingly.


I personally would - adjust the oil cable to spec, use '01 jetting specs, make sure the carbs are "squeaky" clean and ride.
 
I did a 375km loop this past w/end and burned $85 in fuel and used between 1-1.5ltrs of oil. We were operating in mid-range. I'll try to post a picture of my plugs...
 
Cooper0809 said:
I did a 375km loop this past w/end and burned $85 in fuel and used between 1-1.5ltrs of oil. We were operating in mid-range. I'll try to post a picture of my plugs...
Click to expand...

Comparing an apple to an orange via a potato. 375 km = 233-ish miles and 1-1.5 litres = .9-1.3 quarts. Which seems in the ball park of where you want to be. We would need to know what the price of gas was (per gallon/ltr) to figure out a 40:1,50:1,60:1 type number. How you work that right thumb will factor a lot in to mileage so I cant even guess how many gallon/ltrs you got for the $85.
 
I was actually just thinking that I had forgotten to mention I was paying anywhere from $1.40-$1.45/ltr....mostly the $1.40 range. Sled doesn't smoke a lot as I use IPone which I believe is a synthetic oil and if I recall, synthetics will leave a darker wet look on the plugs.
I'm also fairly smooth and easy going on the fun flipper! Conservative I should say...
 
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Well "ball park" numbers (if I am doing math right) is 64:1, a little on the lean side but not absurd by any means, they are known to sip oil. This worked back from $1.40 per liter. The fuel you bought at higher than $1.40 will bring ration down some. Was this before or after you adjusted it to 20mm?
 
I would get an accurate liters of oil to liters of gas before you adjust it. Going to far the other way could get bad quick. I shoot for 1 quart of oil per tank of gas range.
 
Ok so I used 12ltrs of fuel and only burned 250ml of oil. We were operating at low speeds back in the bush on old logging roads, just wide enough for one sled. Temperature was hovering around the 0 mark. Did a couple high speed runs on a lake but could only get it up to 85mph for some reason....might've been because it was so mild and packing snow. But I would think it should've gone faster...anyways, that's what I burned.
 
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