Gear box issue

[Rob Martin]

I have a 2002 Mercury 135 outboard and it looks like the gear box is knackered. Does anyone know if these can be repaired or where I could get a decent reconditioned or second hand one please? Forward gear is ok but it won't select reverse and is slipping. Many thanks

[Mollers]

Originally Posted by Rob Martin

I have a 2002 Mercury 135 outboard and it looks like the gear box is knackered. Does anyone know if these can be repaired or where I could get a decent reconditioned or second hand one please? Forward gear is ok but it won't select reverse and is slipping. Many thanks

That could be a selection issue. If so, it'll be down to cable adjustment or seizure. If it's more serious, it's still fixable by the right man.

[Rob Martin]

Thanks. I think it's more than a cable issue as I tried that but when it is on gear and pressure applied to the prop, it's slipping. Either a new gearbox or new cogs I think but not sure where I'd get that from

[paddlers]

Usually one or two available on eBay, lots in the States. It's probably repairable by someone with the right tools and knowledge.
I'd ring around to get a quote for repair, secondhand ones tend to go for around £350-£400 but you'd need to be confident it's ok. Avoid the Soham con man under his various trade names!
Parts are cheap in the States , just watch for import duty in your sums.

[paddlers]

Usually one or two available on eBay, lots in the States. It's probably repairable by someone with the right tools and knowledge.
I'd ring around to get a quote for repair, secondhand ones tend to go for around £350-£400 but you'd need to be confident it's ok. Avoid the Soham con man under his various trade names!
Parts are cheap in the States , just watch for import duty in your sums.

[Rob Martin]

Thanks

[1eyedjim]

when you say pressure applied to prop do you mean in water or turning by hand?

[Rob Martin]

Originally Posted by 1eyedjim

when you say pressure applied to prop do you mean in water or turning by hand?

I mean basically applying pressure with the boot. It's quite stuff then slips. Also doesn't sound good in reverse gear

[1eyedjim]

if out of water they will lock in one direction and slip (knock in the other)

on my alpha one you have to hold it in the opposite direction to what seems logical

from memory i think it was clockwise for reverse and anti for forwards

[Last Tango]

Not wanting to state the obvious, but this box hasn't been off to do a water pump and the splines on the shift shaft not lined up properly when it was refitted ? The prop on a Merc box will "idle" in one direction in gear when it's rotated by hand and it'll rattle when you do that. The back of the gear dog is "ramped" to allow this.

[Rob Martin]

@tango. Cheers for the message. It's been serviced and the impeller changed. I have thought for the last year or so that selecting reverse causes a lot of crunching and that it can't be doing the gears much good!! It was serviced by a marine mechanic so I bloody hope that it's not as simple as you say. He has been back to look at it since and is going to open the box tomorrow.

[Turbodiesel]

Send it down to us we do gearbox overhauls day in day out!

[Rob Martin]

Where are you based Turbo diesel?

[paddlers]

Rob , one one eBay for a 175 starting at £150 at Canterbury. I've no idea how to provide a link or if the gearing's different for the bigger cc.

[paintman]

This one?
Mercury Outboard V6 Gearbox Also Fits Mariner. | eBay
(I have a 1989 Black Max 135 & according to my workshop manual which covers it the 135 & 150 have the same gearing of 2:1 as does the early 175 but above serial number 6618751 the 175 is 1.87:1. I don't know if yours being 2002 will be different - presumably an Optimax? - but best to check.)

if you click on the link in Turbodiesel's post (black dog) it shows East Looe Cornwall.

They do rattle a fair bit if you engage gear slowly.