Please help with type of screw for outboard

[Steven1s]

Hello, looking for some advice please. I have a Suzuki dt8 outboard, I took this screw out of the hole marked in the image but now it won’t go back in.

It goes in without the plastic washer, but spins with it in.

Does anyone know what this screw and washer is called please?

 

[Rum Run]

That looks like a bespoke type specific to the manufacturer for that job (gearbox filler / level), so not a standard "named" type.
From your description of the problem, either the thread in the hole has partly stripped or somehow the thread on the end of the screw has stripped. Your second picture shows some reduced thread, but I would be surprised if the alloy gearbox could pull the thread off the stainless screw. However, try a stainless steel panhead screw of the same thread as the original but ideally a little longer, plus a stainless washer to spread the load onto the plastic washer. To determine the original thread, take the old screw to a fastener supplier and see which nut fits onto it nicely.
If you can't get a screw the perfect length, a hacksaw is your friend! Or buy one from a proper spares place like Cambridge Outboards.
If the hole in the gearbox has stripped you have an entirely different set of woes and will need to either re-tap the hole a larger size, or helicoil the original.

 

[NormanS]

From the second picture, you can see that the threads of the screw are full of alloy. This tells you that the tapped hole in alloy casing is stripped. The fact that it grips when the plastic washer is removed, means that there is still some unstripped thread in the alloy hole. You might get away with fitting a slightly longer screw. Failing that, the hole would need to be tapped to a bigger size, or repaired with a helicoil. If you take the screw to a supplier of "fasteners", they should be able to help you.

 

[Rum Run]

From the second picture, you can see that the threads of the screw are full of alloy. This tells you that the tapped hole in alloy casing is stripped. The fact that it grips when the plastic washer is removed, means that there is still some unstripped thread in the alloy hole. You might get away with fitting a slightly longer screw. Failing that, the hole would need to be tapped to a bigger size, or repaired with a helicoil. If you take the screw to a supplier of "fasteners", they should be able to help you.

Weird that the "filled" thread is less diameter than the good part of the thread though - I'd guess that the screw thread had gone except that I can't see how an alloy hole could do it.........

 

[MADRIGAL]

Hello, looking for some advice please. I have a Suzuki dt8 outboard, I took this screw out of the hole marked in the image but now it won’t go back in.

It goes in without the plastic washer, but spins with it in.

Does anyone know what this screw and washer is called please?

It is the level plug for the gear box lubricant, and Suzuki should have a part number for it. As others have said, the fact that it spins with the washer in place means that at least some of the thread is stripped. If the problem is the thread in the alloy of the gear case housing, that is a bigger problem than merely replacing a screw.

 

[VicS]

Hello, looking for some advice please. I have a Suzuki dt8 outboard, I took this screw out of the hole marked in the image but now it won’t go back in.

It goes in without the plastic washer, but spins with it in.

Does anyone know what this screw and washer is called please?

As said above it is the gear box oil level screw.

You dont say what year model. I think from 1986 there are all the same but several different numbers for earlier years . You will find the numbers in the parts lists at ( there are 3 plugs all the same)

Browns Point Marine Service, LLC - Suzuki Parts Lookup

As said if the thread is stripped you will have to Helicoil the hole.

(You should not reuse the plastic ( nylon ??) washers )

Quote the year and serial number when ordering

Maybe a good idea to replace the drain screw as well if the slot is damaged ( it looks as though it might be)

 

[Boater Sam]

Looking at high resolution, the thread has disappeared from the end 4 threads on the screw. You need a new screw, the thread in the alloy housing is probably OK.

 

[CliveF]

I think you will find it is M10 thread by 7mm long.
Measure yours and see . Once confirmed get that size of stainless screw unless you get one direct from a suzuki agent.

or try PA Lynch
https://www.palynch.co.uk/search.as...ords=spares&category=33290&page=1&reset_page=

Suzuki Gearbox Oil drain plug 09248-10008-000 but at £8.59 each​

I think I would be sorting one from my local fastenings supplier rather than pay that. Or even fleabay.

good luck