Mariner 2.5hp

M

m1taylor

Well-Known Member
Joined
28 Apr 2004
Messages
366
Location
South Devon
Visit site
Perhaps in one of those moments of madness I put a very low bid in on a problem outboard on ebay - and won it. Well, it's unbelievable - a 2006 2.5 that someone has really abused in the space of one summer. The problem is it's seized! No shifting, so took the head off - obviously never been flushed, some salt crystals even over that short period. The piston is stuck fast - no obvious signs of corrosion above the piston, and the head was not warped - in fact all ok. Gearbox is fne - nicely full of clean oil as you'd expect with it's age. The person I bought it off claims to have bought the engine with a boat, and hence did not abuse it himself! So my theory on the route of the problem - mariner say use 100:1 - to me that's far too little oil for a two stroke - if you got that wrong in the wrong direction, then maybe it would seize.

So what next? I have just started with copious amounts of WD40, and have tried tapping the piston with a wooden dowel. The real shame is, this is practically a new engine!! Any hints on what to try next would be much appreciated. I am used to seagull, and they are built for 40 years plus - this Japanese wonder has not survived one summer of an ignorant owner.
 
[ QUOTE ]
Fill it with Coca Cola and leave it overnight.

[/ QUOTE ]

You learn something new every day! have you tried this and does it work or are you just taking the 'fizz'. Interested to know.
 
If you already have the head off you are ½ way there. Next stage is crack the crank case open and check the crank bearings. These can sieze if the engine has "gone for a swim" and not been properly dried out.

The correct bearings will set you back about £80 a bearing but I am lead to believe you can use a standard bearings from Fenners or BSL. The original has a locating pin to prevent the bearing turning in the housing. The replacement bearing (with out the pin) can be secured in place with "bearing seal".

I repaired one for a friend that had a siezed (rusted solid) top bearing about 6 years ago and it is still going strong not that I would recommend using non OEM parts or anything like that, but.......
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
Well you hit on my worst fear - that despite assurances to the contrary, the engine has had a swim in its short life of previous ownership. However, there is no sign of corrosion in the upper chamber, and no obvious signs of rust on any other steel parts. I will try the coke method - diet or regular (or with a cherry twist?)?
 
[ QUOTE ]
Fill it with Coca Cola and leave it overnight.

[/ QUOTE ]

That's precisely how we used to clean the radiators on our Mini's back in the sixties! Much less expensive than the branded cleaners.
 
I would not use coke. First you have to get it into the crankcase then you have to get it out again. HTF do you propose to get rid of the sticky mess left in the engine?.

As I said, you are ½ way there already. Split the crank case and examine the insides for any signs of corrosion and in particular check the bearings and seals.

Also, with the crank case split you have a better chance of tapping out the piston as the crank will be free.

I assume you already have the start mechanism and flywheel off. /forums/images/graemlins/confused.gif
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
Thank Cliff - yes, the starter mechanism is off, as is the fuel tank and head - that was all very easy, being a 2006 engine with new screws/nuts etc. I am hesitant to go further without a workshop manual - there aren't any on-line versions by any chance?
 
Assuming you have stripped the top end and the crankcase and barrel have been removed from the leg (6 or 8 bolts underneath) then the crank case is split by removing 4 or 6 bolts around the "lower" case to "upper" case/cylinder and tapping gently to crack the case open - simple.

Reassemble using a smear of hylomar (no gasket!).
If fitting non OEM bearings use plenty of "bearing lock" around the bearing housings. Do make sure the bearing outer race and the housings are clean and free from any oil or grease before applying the "bearing lock". There is nothing complicated in these little engines.

Just a thought..... The engines do not have a gear shift do they? so the prop is permanently "in gear" - have you checked the lower gearbox is free. That is does the drive shaft turn freely with the engine removed from the leg?
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
If it makes you feel any better this is probably not an abused engine. I flushed mine every time until one fateful evening when I arrived home late. It hadn't been inverted, just laid flat in the car for the 2 hour drive home. Took it out of the car when I got home and stood it up in the garage for 6 days - seized! (a good sharp pull freed mine)

The good news is .... Most 'seized' Mariners will provide good service, especially if run on 50:1. And you are in good company. If you know the difference you can play spot the 'seized' mariner on those hot summer evenings. There are loads about. They sound very different. /forums/images/graemlins/smirk.gif
 
Thanks for that - the obvious thing is WTF do they tell people to put in 100:1 in the first place? To me, that asking for trouble. I have a seagull from 1959 running on 10:1 - so much oil I doubt it will ever seize or wear out.
 
You must log in or register to reply here.

Other threads that may be of interest

P
Removing antifoul back to Gelcoat
2 3
Replies
58
Views
2K
Gixer
Gixer
N
Bukh replacement
Replies
3
Views
289
LittleSister
LittleSister

Share this page

Top