My new ride..an old 720

[Tazza]

So I cranked down the manifold this morning after the high heat RTV set overnight and fired it up. I started right away and ran way smoother. I had a vacuum gauge on the intake and as the seconds went by, the needle smoothed out and the vacuum increased, indicating the valves were seating again. Yeah! I set the idle speed and governed speed and ran it for 15 minutes. It's much better and runs great again. Going to get it off the trailer and plow the driveway and hopefully she'll be back in good working order. I checked the compression after it ran for 15 mins and #2 is still only 30 psi with the others at 60. It may come up as it runs in. I didn't want to get into a valve job at this point, broken head bolts etc. but will do it this spring when it warms up and drys out.
What I learned here, is valves can go out of adjustment and should be checked more regularly. I only have 200 hours on the machine since I bought it so maybe a tune up every 50 hours is in order.
Thanks to all who helped, much appreciated.
I think that's it for now.
Cheers

It's still a bit odd that you have one that is quite a bit different, hopefully it will find it's place and even out.
Glad it's working well again.

 

[kilohertz]

It's still a bit odd that you have one that is quite a bit different, hopefully it will find it's place and even out.
Glad it's working well again.

Well it seems to be fixed and working even better today. I ran around the yard and plowed the driveway and such for 2 hours, running it about 2500 RPM and watching the vacuum gauge. Wow! Is it ever nice to be able to move forward AND get the bucket up and down all at once. Engine hardly slowed down at all, what a difference. This is the best it has run since I bought it 3 years ago. Putting in a Diesel on hold now...this works too well. After the 2 hour run I checked compression and have #1- 60, #2-35, #3 65 and #4-50. Hopefully #2 will settle in after a while but either way, the machine runs great now. The plug color was perfect and all cylinders seem to be firing just fine.
Cheers!

 

[Tazza]

Well it seems to be fixed and working even better today. I ran around the yard and plowed the driveway and such for 2 hours, running it about 2500 RPM and watching the vacuum gauge. Wow! Is it ever nice to be able to move forward AND get the bucket up and down all at once. Engine hardly slowed down at all, what a difference. This is the best it has run since I bought it 3 years ago. Putting in a Diesel on hold now...this works too well. After the 2 hour run I checked compression and have #1- 60, #2-35, #3 65 and #4-50. Hopefully #2 will settle in after a while but either way, the machine runs great now. The plug color was perfect and all cylinders seem to be firing just fine.
Cheers!

That is great news, a diesel would use less fuel, but as the engine in it now is working as it should, it's not worth the effort and cost.
Happy plowing!

 

[OldMachinist]

That is great news, a diesel would use less fuel, but as the engine in it now is working as it should, it's not worth the effort and cost.
Happy plowing!

I saw you mention .008" as the tappet clearance, that's what the intake get set to. The exhaust should be .016" cold.

 

[kilohertz]

I saw you mention .008" as the tappet clearance, that's what the intake get set to. The exhaust should be .016" cold.

Yes OM, that's what I set them too, I mentioned in my post .008 and .016 but forgot to mention IN and EX.
Running great, and all is well.
thx

 

[Mikefromcny]

Yes OM, that's what I set them too, I mentioned in my post .008 and .016 but forgot to mention IN and EX.
Running great, and all is well.
thx

I'm not sure what a tight VH4D would have for compression #'s, but my 610 had around 75 psi in all cylinders. Started easy and had good power. Ive heard air cooled, gas engines such as the wisconsin are good for about 1500 hours. I've also seen gas engines last much longer. Frequent oil changes and making sure the air intake from the filter to carb is sealed up good will definitely make them last longer.

 

[kilohertz]

I'm not sure what a tight VH4D would have for compression #'s, but my 610 had around 75 psi in all cylinders. Started easy and had good power. Ive heard air cooled, gas engines such as the wisconsin are good for about 1500 hours. I've also seen gas engines last much longer. Frequent oil changes and making sure the air intake from the filter to carb is sealed up good will definitely make them last longer.

Funny how things come back around...I just found my old post with a lot of history that I had forgotten about...seems this adventure was just about letting enough time go by for the carbon to fill up the intake port area...I was fighting a battle that had been building for years. Now that I have the head off, and see the extent of the problems, all of my notes and comments make more sense....mmmm? Maybe a Diesel is in order. Now waiting for the rains to stop so I can continue work. More later....the adventure continues.