billskip
Well-Known Member
Can't find my manual maybe I gave it to someone...but these people list parts and maybe identification...
Mariner 60 HP 2 stroke- gearcase screws?
- Thread starter sparkie
- Start date
sparkie
Well-Known Member
Thanks for that, I'll check it out later. Cheers.
Seastoke
Well-Known Member
Hit the head with a mallet and right sized screw driver , helps crack seal, also remember you get more torque the longer the screw driver. I don’t think an impact will have a big enough head.
sparkie
Well-Known Member
Yes I'll go equipped with mallets and screwdrivers, and hopefully they will shift... Probably been a long time since they did, despite engine having full service history......!!
Boathook
Well-Known Member
I struggled to remove the screws on my Honda one year and it was done each year.
Worth putting new sealing washers on or if the screw head is damaged invest in some new ones to make future servicing easier.
sparkie
Well-Known Member
Yes good advice. Cheers.
sparkie
Well-Known Member
Hi, finally managed to get the screws out ok, bit of heat and the impact driver, the left hand one is definitely the vent/fill for the gearcase, the right hand one I can't figure out at all. Its exactly the same screw, but behind it is just a void, all that's there seems to be the gearshift rod. Very odd. Doesn't seem to have a purpose but it must be there for something... The parts diagram (thanks Bill) doesn't show it, but strangely enough the parts list specifies 3 number, so all very confusing.
billskip
Well-Known Member
Well done for getting them out, I do remember my Mercury had two screws and I used the bottom and vent for filling.
Like you I haven't a clue now what the other is for, I think my 80+years old memory is playing tricks thinking it was a filling hole. Sorry can't find workshop repair/parts manual,can't remember what I've done with it.
Boathook
Well-Known Member
Is it for connecting a hose to use for cooling water rather than using the muffs ?
sparkie
Well-Known Member
No I think not, no signs of water, or oil for that matter, but I think it must be another vent for the gearcase for some reason. Perhaps there's an internal airlock if you only use the LH one. Anyway I'll take both out when I'm refilling and see what happens. Cheers.
jfm
Well-Known Member
Good going getting the screws out. A few quick comments:
1. As some have said, you MUST refill the gear case oil from the bottom screw not the top one - the top (aft) one is only a vent for when you fill it from the bottom. You need to buy the oil in toothpaste tubes or get one of those tiny pumps, to allow you to fill from the bottom.
2. The forward top screw seems to be there to flush only the shift shaft. It is not to flush the engine power head because it doesn't connect to the pressurised side of the cooling water loop
3. Mercury do a hosepipe connection for the forward screw hole to connect a hosepipe, though I'm not sure I'd bother - I would just hold the hosepipe over the hole. https://www.boats.net/product/mercury/16841Q02
4. Exploded diagram is here - this gives you all the part numbers to replace the screws. Boats.net are excellent and they ship everywhere including UK. When buying parts remember that your gearbox is the 135mm torpedo tube version (can tell that from your photo). https://www.boats.net/catalog/mercu...999/gear-housing-driveshaft-1-64-1-gear-ratio
5. Given that your screws were seized, the whole gearbox might be seized onto the leg. In your shoes I would remove the gearbox and refit it, to cure any seizing there. Simple enough job. While you have the gearbox off, you can fit a new water pump impeller.
1. As some have said, you MUST refill the gear case oil from the bottom screw not the top one - the top (aft) one is only a vent for when you fill it from the bottom. You need to buy the oil in toothpaste tubes or get one of those tiny pumps, to allow you to fill from the bottom.
2. The forward top screw seems to be there to flush only the shift shaft. It is not to flush the engine power head because it doesn't connect to the pressurised side of the cooling water loop
3. Mercury do a hosepipe connection for the forward screw hole to connect a hosepipe, though I'm not sure I'd bother - I would just hold the hosepipe over the hole. https://www.boats.net/product/mercury/16841Q02
4. Exploded diagram is here - this gives you all the part numbers to replace the screws. Boats.net are excellent and they ship everywhere including UK. When buying parts remember that your gearbox is the 135mm torpedo tube version (can tell that from your photo). https://www.boats.net/catalog/mercu...999/gear-housing-driveshaft-1-64-1-gear-ratio
5. Given that your screws were seized, the whole gearbox might be seized onto the leg. In your shoes I would remove the gearbox and refit it, to cure any seizing there. Simple enough job. While you have the gearbox off, you can fit a new water pump impeller.
sparkie
Well-Known Member
Thanks very much for that info, all is now clear! Although why one would need to flush the shift shaft housing I'm not too sure? Anyway I can now proceed with the drain and refill knowing what I'm doing..... Thanks again.
