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Discussion Starter · #1 ·
JUst looking at my piston wash and I could swear that my PTO side is burning a bit leaner than the mag side. Anyone seen this before? Everything should be nice and clean in the carbs and I'm having a hard time coming up with a reason. Maybe this is just a trait of the engine?
 

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A few comments that came to mind when reading this

1. I have always heard that the MAG cylinder is going to run a bit cooler since the water pump is on that side. That difference in running temp could be the difference you are seeing?

2. The 700's and 800's are notorious for loosing the crank seal on the PTO end. Mine just locked up the PTO side last season after the seal failed, sucking air into the PTO cylinder and running it lean. You may want to pull the clutch and then the seal out and check it or replace it.
 

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Discussion Starter · #4 ·
Ya, may be the seal....I'm running 440 mains but when doing compression check I am about 5 lbs lower on the pto side.
 

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yes , defiantly something wrong, with 440s your plugs would be black
 

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Discussion Starter · #6 ·
Question is should I be concerned with this? I am planning on doing a rebuild in summer and would prefer to ride the season out with what I have. My compression is 110 Mag and 105 PTO. I will post some pics of the plugs hopefully tonight. When looking in through the plug holes I can see that the piston wash is about perfect on the mag side and a hair lighter on the PTO. The engine still feels strong when running it...pulls pretty good. The only thing I notice is that it loads upo a bit at idle....to about 3500 rpm when hot but idles at 2000 nice when cold. I am assuming this is just due to the pipe heating up.
 

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assumming your guage is correct,,,they are low
you should be at 125lb say at 1000ft elevation,
 

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My 700 at 7000 miles was 145 lbs before rebuild on a quality brand gauge. 150 lbs now after rebuild at 800 ft elevation. As a note engine ran strong and I rebuilt before I had a problem including new bearings (wide pto), seals, pistons (Pro-Lites), rods. Crank trued to within 1/2 thou all for less than $800 my garage cost. (tear down found bearings were going and glad I did it.)

If you have a CDN Tire gauge go rent or borrow a good one for accurate numbers.
 

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a little note: PTO crank seal requires complete engine dissasembly. they put a little flange on the seal to keep it in place, so the lower case half needs to be seperated. the downside is that the lower jug nuts need to be removed to do this (studs run all the way to the lower case). if you are carefull, you can keep the jugs and head attached to the upper crank half while working with the engine upside down. the drawback is the base gasket is releaved of pressure and then torqued down again. not really reccomended.

in your case with the somewhat low PSI readings, i think it would be a wise idea to freshen up the rings and possibly pistons as well (depending on condition).

this is all assuming that the crank seal is indeed out of spec and that the PSI gauge is giving an accurate reading. im not too sure i'd wait until summer time to consider an engine rebuild. if you've got all the parts lined up, its an easy 1-2 day job. an extra set of hands is also a good idea.
 

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Discussion Starter · #10 ·
Oh ya...my elevation here is about 1750 feet so I should be running around 120-125 psi I would think.
 

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Discussion Starter · #11 ·
So what should I be looking for when checking the crank seal? I shouldn't have to pull the clutch as I have a tool called a see snake to look around the clutch area. Should I be looking for cracks? Oil leaks or seapage? General grunge around the carnk where it enetrates the crank case? Not sure what to look for.

Another thing.....I was always told that if your compression was within about 5lbs per side then you were fine...any comments on this?
 

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You may see seepage but the vacuum draws into case when seal leaks. 5 lbs comp within cylinders seems acceptable, your gauge may just read low.

Laker220 nice to see you on HCS. Did you get the cd I sent you?
 

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Discussion Starter · #13 ·
You may see seepage but the vacuum draws into case when seal leaks. 5 lbs comp within cylinders seems acceptable, your gauge may just read low.

Laker220 nice to see you on HCS. Did you get the cd I sent you?[/b]
Ya...decided to come over from the darkside to HCS. Nope, didn't get the cd yet but usually with the mail system a week wouldn't surprise me for the delivery. Thanks again...greatly appreciated.
 
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