Mariner 4/5hp 2 Stroke Rebuild.

[Mark-1]

A mate who watches too much Allen Millyard on YouTube has convinced me we should do top and bottom end on my rattly 2001 5hp Mariner 2stroke.

This is purely for the challenge of doing it - the engine was going on eBay for spares/repairs anyway.

I've got the Clymer Manual.

Any hints or tips?

Anyone suggest somewhere better than Ebay to source Crankshaft parts, bearings, piston rings, piston etc?

 

[Paul1962]

Hi - rebuilt mine (well Tohatsu 5hp - same thing different badge etc) last year. Really simple nice to do. E-Bay for me was the best choice. I replaced my crankshaft seals with Viton items. I do have a new pair I can send
if you are interested. Is £6.00 including postage to mainland UK of interest? I attach a Tohatsu Owners manual for interest.

Regards

Paul

 

[Mark-1]

First night. Drive shaft is stuck solid in the spline, so I can't even separate the engine from the OB. Engine is upside down in the garage with penetrating oil sprayed down the shaft.

Lesson learned. Changing the impeller regularly is not just about changing the impeller, it's about lubing the spline regularly.

(I had been considering buying a Honda 2.3 on the basis it was air cooled and therefore didn't need regular impeller changes - I was wrong. Sooner or later the gearbox would need to come off, and without regular removal there's a good chance it would be seized.)

Yes, I've been very naive about outboard maintenance, hitherto. ?

 

[northwind]

As you are finding the biggest issue is seized bolts, start spraying them all with pentrating fluid to see if you can soak some in over time. Remove the 6 bolts that hold the powerhead onto the leg and remove these, then you can try moving the head off the leg from the top. You may need to apply some pressure to break the old gasket seal between the head and leg.

 

[Mark-1]

As you are finding the biggest issue is seized bolts, start spraying them all with pentrating fluid to see if you can soak some in over time. Remove the 6 bolts that hold the powerhead onto the leg and remove these, then you can try moving the head off the leg from the top. You may need to apply some pressure to break the old gasket seal between the head and leg.

Incredibly I sheared zero bolts tonight. I was expecting several.

Then driveshaft spline however is utterly welded. Apply some pressure? We did. A lot. Plus gas is gonna have to take the strain for a few days and I'll give it another go. 99pc of tonight's effort was trying to lift (hammer/lever) the head off the leg. Next time I'm going to try wedges/prising between the lower unit and the leg.

Good news is the bore is not scored. Looks good.

 

[northwind]

Incredibly I sheared zero bolts tonight. I was expecting several.

Then driveshaft spline however is utterly welded. Apply some pressure? We did. A lot. Plus gas is gonna have to take the strain for a few days and I'll give it another go. 99pc of tonight's effort was trying to lift (hammer/lever) the head off the leg. Next time I'm going to try wedges/prising between the lower unit and the leg.

Good news is the bore is not scored. Looks good.

Can you drop the lower leg a bit? Can you get it low enough to access the bolts on the pump / to remove the gearbox top? Accepting that the shaft is stuck in the head, if you can remove the gearbox, you can then remove the head with the prop shaft attached, and work on it on the bench.

 

[Mark-1]

Can you drop the lower leg a bit? Can you get it low enough to access the bolts on the pump / to remove the gearbox top? Accepting that the shaft is stuck in the head, if you can remove the gearbox, you can then remove the head with the prop shaft attached, and work on it on the bench.

That's a superb idea I hadn't thought of and opens up a load of options, thanks. I'm not sure if there's space yet but there is a gap so I can't be far off.

 

[ghostlymoron]

This is a blast from past. My first outboard was a mariner 4 long shaft. Bought it at Gloucester boat jumble for my Leisure 17, knowing nothing about them I was lucky to have picked this one. Completely reliable and never let us down.