Awakening a Holt 75 Engine from a Nap?

Long time tractor enthusiast, first-time poster here. I need some help with awakening an old Holt 75 engine from a 2-year nap.

A little back story on the engine: (*placer holder for the year/serial number, additional info*). The engine is owned by our local tractor club and is currently mounted to a heavy steel frame. To be clear, the unit in question is the engine only, not a complete 75 tractor. The engine is complete forward of the flywheel. It has a belt pulley attached aft of the flywheel with an over-center clutch, but I am unsure if this is original. This engine was last running at least two years ago. At that time, the engine was very difficult to start and would cough, misfire and backfire frequently.

I have taken on the task of getting this Holt engine running again for our late-summer show/threshing bee. I am comfortable turning a wrench and doing basic- to moderate-difficulty operations. However, I have never worked on anything this old. I found a scanned copy of the operators manual for the engine online and have been studying it.

My plan for the engine was to start with a basic tune-up:

1. Remove, inspect and clean spark plugs.

2. Squirt oil into the decompression cups, priming cups and spark plug holes to get oil back on the topside of the pistons.

3. Gently work the engine back-and-forth to get the cylinder walls coated in oil again.

4. Verify while rotating the engine that none of the valves have stuck.

5. Adjust all the valves. Per the operators manual, all should be 1/32" clearance, right?

6. Oil all the rockers and the top end of the engine.

7. Adjust point gap in the magneto. Note: I could use some help/instruction on this step. I have done point gaps in automotive distributors, but never a magneto. Also, per the manual, this gap should be 1/64", correct?

8. Inspect/clean carburetor. Note: help with the carburetor would also be appreciated.

9. Refill and apply grease to all the grease cups.

10. ??? I am sure I am missing steps here...

Does anyone have recommendations on materials to read for working on this engine?

Are there any other systems or components (governor, mechanical lubricator, etc.) that need attention to awaken this engine?

Looking forward to this discussion!

Thanks in advance for the help,

Nick

Hi there. I wrote a nice long post of what’s causing your symptoms and what all to do, but the good old ACMOC site decided to throw a fit and it went away. I’ll reach out via the private message system and we can talk on the phone.

Regards

Bruce P

BP: So awesome of you to help this gentleman with their 75 engine. I hope they get it dialed in and share details about it soon. JM

Bruce P-

I look forward to your message and phone call. Thank you in advance for your time and assistance.

Nick

Hi Nick. I sent you a message via the ACMOC private message system. It should pop up when you log in next, or you might have to click on the “in box” button.

BP.

Bruce -

It took me a bit to find it on mobile. I replied to your PM this evening.

Thanks!