Mercury 402 jumping out of gear

[law1@cwcom.net]

Hi
New to Iboats hope you can help,I have an oldish mercury (1978) 40 hp 402 out board started not driving on full power,been useing it this summer fine then last week had trouble finding neutral,and then as above.Anyway took gearbox off leg and after a bit of fun taken prop off.
How do you strip out gear assembly,
I see the casting as a internal large thread on it with internal Castellated nut do you remove this nut to expose gear train and make repair or inspection.
Have tried to tap this nut around but only Succeeded in breaking bits off the Castellation have left to soak in penertating oil I have the workshop to make spanner to remove this nut if it i am on the right approach

(I have a an orderin the post for manual but keen to get on with repairs)

 

[Laddies]

Re: Mercury 402 jumping out of gear

You have to remove the inter al nut that you speak of, in most case they come out fairly easily but in salt or corrosive water they may have to be drilled and broken to remove

 

[law1@cwcom.net]

Re: Mercury 402 jumping out of gear

Thanks for that,yes I guess salt water and corroried,just to be sure the size would be about 55mm. is that the one with a castlation on it.
stuart

 

[Laddies]

Re: Mercury 402 jumping out of gear

I am not good with MM but 55 would be about 1.77" by my figures and the nut inside the gear case that retains the carrier is about 3 to 3.5 inches OD. If we are talking about the same part and you engine is a salt water engine you will have to drill a series of small holes across the nut in four places and use care when breaking the nut. If your not a experienced mechanic you might consider taking it to a good repair shop

 

[law1@cwcom.net]

Re: Mercury 402 jumping out of gear

hi
think that we are on about same retaining nut,Your probably closer than my self in size measured it at 70mm od tonight,started to make a castleated spanner to remove the nut but drilling it out would be easy ,er up until the point where you building it back up.
(Is this normal practice to cut it out)
when i get nut out in one piece or bits,what do i look for in repairs or gears.

ps thanks for letting me know I am on the correct course so far been very helpfull look forward to more feed back
stuart