Old Mariner 30 - Head/Inlet Bolt bolt

HughN · 13 April 2014, 18:51

The gasket between the block and the reed/inlet 'head' on my 1991 Mariner 30 2 stroke started to 'chuff', puffing white smoke out of the gasket. One of the M6 bolts goes into a casted boss that has a stripped thread. I am hoping for some advice / options....

The boss is at the bottom of the block and highlighted in the arrow below; the bolt threads in from right to left in the photo.

The threaded hole continues through the boss and comes out right against the main part of the casting, i.e., I couldn't get a nut or bolt-head in there.

To helicoil it would mean drilling it out by another 3mm or so, leaving only about 3mm of material round the threaded hole. This seems a bit too little to me.

I could drill it out to 6mm and grind the head from a bolt so that it would slide in from left to right, then have a nut holding things together.

On the plus, side, the engine does seem nice and clean inside...

All suggestions gratefully received!

Seaflyer02 · 13 April 2014, 19:09

Is it possible to take the part off? if so you could take it to a local engineering company (one that works/welds aluminium) and ask them to weld it up, once welded just needs re-drilling with a small stand drill and tapping back out.

If they offer to weld in situ be very careful because of associated electronics, battery etc.

A1an · 13 April 2014, 19:20

Without seeing it in my hands its hard to say what state the old threads are but could you re tap it back to the existing thread, make a stud and stud lock it in there?

HughN · 13 April 2014, 19:33

Quote:

Originally Posted by A1an

Without seeing it in my hands its hard to say what state the old threads are but could you re tap it back to the existing thread, make a stud and stud lock it in there?

Now that might be a good idea!

HughN · 13 April 2014, 19:34

Quote:

Originally Posted by Seaflyer02

Is it possible to take the part off? if so you could take it to a local engineering company (one that works/welds aluminium) and ask them to weld it up, once welded just needs re-drilling with a small stand drill and tapping back out.

If they offer to weld in situ be very careful because of associated electronics, battery etc.

Bit of a pain because it is the powerhead but I may know someone with the skills to do it in situ.