Simms pump drain plug - Lehman 120

My drain plug is leaking. What is the screw size? I want to order a dozen crush washers. I'm not at the boat this week.

Thanks in advance.

Can't help other than to suggest calling American DIesel who are the Lehman guys.

As the plug threads into AL, give some thought into replacing the drain plug with a small valve? Some have used ice-machine valves but the threads are typically weird English threads, might be Whitworth even. You will have to get someone to make an adapter for you but it will eliminate the stripped threads and metal contamination or no oil you will inevitably face.

In the short term, just anneal the washer and reuse.

Greetings,
Mr. w. I vaguely recall the drain plug was VERY small 1/4-28 or some such. I seriously considered replacing it with a valve as Mr. X suggests but I felt, and I still do, that the largest drain hole I could put into a 1/4" bolt (new valve body) would be in the neighborhood of 1/8" so VERY slow drainage. The ONLY option in my case would be to drill the drain hole larger, re-thread and put in a suitably large valve. I wouldn't dream of doing this with the pump in place and it isn't quite enough of a PIA (yet) to take the pump out and do it properly...Yup, anneal the copper washer and re-use.

Ahh RT, you have the wrong attitude! The oil will be hot and full of diesel so you put a leetle hose on the valve and put the other end in an old milk bottle (or whatever) and go pour yourself a beverage, watch the sun do its thing and sometime later, after you are suitably mellow, you go back to where your engine is stored, close and lock the leetle valve and pour in the premeasured amount of oil (you never remove the level plug because being British, it's going to strip too). Ergo bingo, all is good in the world and depending upon your choice of beverages, you have a useful bottle to drain Simms oil into the next time.

"Yup, anneal the copper washer and re-use."

Good plan although the anneal technique for copper is different from iron or steel.

Most auto supply or True Value will have copper washers of many sizes.

Mine stripped out last year.

It might have been 5/16 as I tapped with a new, cut off fine thread 3/8 bolt.

For my fl120, I bought an m8 (I think) male-barb fitting on line. It screwed right in. On the barb side, I attached a short 1/4 inch pex tube after flaring it on the barb side. On the other side I used a1/4 inch barb and attached a 1/4" ball valve. To be sure, I also used a cap (female plug). Now my pump oil change is a simple turn of valve, no spills. Harbor freight sells a copper washer assortment. A no brainer buy. I used some of same under the valve cover screws. No weep anymore, and they don't seem to need retourqing as often.