Need more help from the pros/ Tightening lower unit drain and vent plugs

[Douglasdzaster]

Hello everyone, Thought I’d check in with y’all.
my 1992 Yamaha 40mshq was leaking out of the lower unit drain plug. When I removed it it wasn’t tight at all. I replace the black gaskets every time I change lube. I probably didn’t tighten it enough. I stopped when I hit bottom and I put a wrench on the screwdriver and snug it up. I do worry about over tightening.
I drained it and ready to refill. However I can’t find the torque value for those screws anywhere in my manual.
I have a little 1/4” drive torque wrench I could adapt a flat head bit to as well as a 1/2” drive torque wrench.
So far the 1/4” has covered everything on the power head.
Does anyone know if there is a torque for these screws or have advise on how I should tighten them properly without over doing it?

[99yam40]

I just snug it up and then come back later and do it again.
the washer compresses some over time

[Douglasdzaster]

I stumbled across Yamaha’s maintenance update about going to the black gaskets in 2016 and how it’s a different installation procedure. Apply clean oil to the threads and on both sides of the gasket. Tighten until seated then an additional 45 degrees to achieve proper torque or tighten to and they show some formula that I couldn’t fallow. 7 51 Nm (0.7 + 0.1 m-kgf,5.2 50.7 lb-ft).
Dont know why they can’t just list Nm or inch lbs. I fallowed the instructions. Got it snug with my screwdriver and put a wrench on it but I didn’t go a complete 45 degrees. Felt like it was to tight. I’ll check it later and see how it feels. I was worried I may have over done it on the gasket on the top plug. But when I removed the pump from the drain it was barely letting any oil come out so I figured it wasn’t sucking air.

[HMBJack]

Years ago, like ten years ago, I remember Yamaha's gaskets were a rust colored type and they were a tad too hard. They loosened up no matter what.

Then Yamaha went with a black colored gasket. I have never had a problem with these.

I go to to reasonably "snug" then add a 1/3 or 1/4 turn. No need to go Gorilla on these...

[DennisG01]

I've never put a torque wrench on a drain/vent screw in any type/brand of engine I've ever owned or worked on. You can "feel" when it's tightened correctly. I'm betting, like you said, for some reason you just didn't tighten it enough.

[panasonic]

I stumbled across Yamaha’s maintenance update about going to the black gaskets in 2016 and how it’s a different installation procedure. Apply clean oil to the threads and on both sides of the gasket. Tighten until seated then an additional 45 degrees to achieve proper torque or tighten to and they show some formula that I couldn’t fallow. 7 51 Nm (0.7 + 0.1 m-kgf,5.2 50.7 lb-ft).
Dont know why they can’t just list Nm or inch lbs. I fallowed the instructions. Got it snug with my screwdriver and put a wrench on it but I didn’t go a complete 45 degrees. Felt like it was to tight. I’ll check it later and see how it feels. I was worried I may have over done it on the gasket on the top plug. But when I removed the pump from the drain it was barely letting any oil come out so I figured it wasn’t sucking air.

Where can one find this maintenance update you speak of?

From above I assume it says 7.5 NM which is 66 inch pounds. That sounds like a reasonable torque on the drain screws.

66 pound inch in case Boseco is watching..lol

I, like most don't torque these screws...just snug them up and recheck them after a few hours.

I think having a good screwdriver that fits the slot in the plug is key as well. Seen so many plugs torn up from using a crappy screwdriver....it is hard to know how tight you are getting it when the screwdriver is slipping..

[DennisG01]

I think having a good screwdriver that fits the slot in the plug is key as well. Seen so many plugs torn up from using a crappy screwdriver....it is hard to know how tight you are getting it when the screwdriver is slipping..

Agree! I bought a cheap set of screwdriver "sockets". It goes on a socket wrench but is a screwdriver. Got them from Harbor Freight. I used the biggest one (which is quite a bit larger than they typical "large" flathead) but had to grind it thinner just a tad. Fits REALLY well - and I use a shorti socket wrench with it as it's easier to keep it from slipping out due to holding the wrench at a bad angle.

[boscoe99]

Where can one find this maintenance update you speak of?

From above I assume it says 7.5 NM which is 66 inch pounds.That sounds like a reasonable torque on the drain screws.

66 pound inch in case Boseco is watching..lol

I, like most don't torque these screws...just snug them up and recheck them after a few hours.

I think having a good screwdriver that fits the slot in the plug is key as well. Seen so many plugs torn up from using a crappy screwdriver....it is hard to know how tight you are getting it when the screwdriver is slipping..

After years of mis-expressing torque, Yamaha has finally gotten it right. In some documents anyway.

[pstephens46]

Let’s give Roscoe credit for his proper influence on Yam publications!!! I’m busting chops of course. I cringed a bit when OP mentioning using the wrench on screwdriver to tighten. I had to use one to loosen one once when I bought my boat.