new member with a 680 Hydro, thanks for letting me join

[kellycaudle]

Should I have painted the box before I installed it?

 

[mgonitzke]

If you would like for the steel parts to not rust, I'd paint them.

I would recommend some sort of high temperature paint like BBQ grill paint, as normal paint will burn off.

 

[hydroharry]

Kelly - things are starting to look good. You didn't mention if you also got the "muffler crutch" from David Kirk that I recommended.
https://www.kirkengines.com/index.php#MufflerCrutch
It's really a must have. It will save the aluminum duct backing plate from cracking (which is expensive to replace).
I'd get the crutch, remove the box and paint it, then install the crutch and the box. You'll be all set for 20+ years.

 

[kellycaudle]

Yes, all the pictures I see are painted so I will paint using high temp product. It will also help hide it from the front when I get the grill and lights on.

 

[kellycaudle]

[I wondered what that piece did- I've seen it before. Thank you. I will get that asap. I don't want to have to replace the plate when Im saving up for the grille assembly plus head lights.$$$$ Thanks again!!

 

[kellycaudle]

Kelly - before you go getting the tin muffler box have a good look at the aluminum duct on the back side of the muffler. It should have several screw holes where the tin (actually very light steel) muffler box is held to it with screws. Often times this aluminum duct is cracked or the screw holes are wallowed and won't hold the parts of the tin box. I see Charlie at CC Specialties has the tin muffler box, and price is fairly reasonable for a brand new box. Charlie also has the aluminum duct the box mounts to but make sure you're sitting down if you need one.

Also, David Kirk at "Kirk Engines" (linked above at the colorful boxes too) has an item he calls the Muffler "Krutch", ops guess he really calls it Crutch. This thing really works and will save your aluminum duct plate from cracking. See it at this link.
https://www.kirkengines.com/index.php#MufflerCrutch

I was very interested in the Crankshaft balance plate that is offered

My unit still has the vibration even after a I installed new engine mounts. Now I know why it still has the vibration and I want to fix that. Is the K301 engine easy to dissemble and put back together?
Thanks, Kelly

 

[kellycaudle]

Kelly, WELCOME!

Hydro, it should have a K301, being of that vintage (~1982) I would assume a K301AQS.

View attachment 139061View attachment 139062

Yes that is the K301AQS engine. Cant believe how strong it is. This flyer is great- thanks

Kelly from SC

 

[hydroharry]

Kelly - there are alot of guys that would say it's fairly easy to disassemble a K301AQS and put it back together - but all of them have done it several times. It's alot to go thru and I'm not sure how much you would really improve a K301AQS (12hp). The balance kit that David Kirk has is generally for Kohler engines with balance gears, and I don't think your K301AQS even has balance gears. In the pics of the engine you posted earlier I can see the dip stick on the top of the engine. I believe it goes thru a hole directly thru the top of the block. If so, you won't have balance gears. (If you look and can see the access is actually a shoulder mount on the side of the block then you have balance gears).

I'm not familiar with the engine mounts used on a model 680 but even tho you've changed them they could still be more of the problem you are experiencing.

Hopefully others on here will provide more info to help you.

 

[mgonitzke]

What did you use for new engine mounts, and how tight did you tighten them?

 

[kellycaudle]

I ordered them from CC Specialties and they went right on no problem and what ever the torque requirement was Im sure I went to the spec. Is there something I missed or should have verified?

 

[mgonitzke]

Use original length bolts and a new nylock nut on each bolt, tighten so that 1-2 threads shows through the nut. If you use the included instructions, you will probably overtighten them.

They also will "break in" a bit after a few hours. Make sure the engine is running 3600 RPM at full throttle too...they are really designed to damp out the engine vibrations at that speed, so if the high speed stop is not set right, it may not be operating in the optimal damping range for the mounts.

 

[kellycaudle]

Use original length bolts and a new nylock nut on each bolt, tighten so that 1-2 threads shows through the nut. If you use the included instructions, you will probably overtighten them.

They also will "break in" a bit after a few hours. Make sure the engine is running 3600 RPM at full throttle too...they are really designed to damp out the engine vibrations at that speed, so if the high speed stop is not set right, it may not be operating in the optimal damping range for the mounts.

Interesting- thanks for the guidance and I will check this!

 

[kellycaudle]

Muffler box installed and painted with high temp. 680 Hydro
Kelly in SC

 

[kellycaudle]

a couple more pic of the muffler shroud install before paint

 

[kellycaudle]

Welcome Kelly - your 680 looks like a nice machine (from the distance in your pic). When are you planning to retire (and restore)?

2026!! but, if I can somehow finance a shop before then I will restore starting at that moment. I hate to my machines sitting out in the weather under cover

 

[lpalma]

Looks fine from Joisey, as you know, once you have one, you will need anudder.

 

[kellycaudle]

I have the Hydro 680 with the 38" deck - 35719X 38C, serial number 0320025U. The "PTO to deck" belt belt currently slips under load. I want to get the correct belt this time. I have identified PN# IH-473462-R4 3/8" x 81" as the belt to order. Can someone verify this? thanks