Flushing 2HP Yamaha after use

[pagoda]

We have a venerable 2HP Yam (Pre -cdi) which in the past was run in a dustbin of freshwater after use in the sea. That was mainly when the engine was used for pottering around the nearby coasts in fine weather. A dustbin was ideal because the engine is permanently in gear - no reverse, and the prop always turns.
As the engine has been promoted to push a new small inflatable tender, we don't have that luxury of vast containers of fresh water at sea.
The input to the water pump consists of 3 or 4 small holes in a row - just under the cavitation plate -which makes the use of almost any "water - flush- muff" impossible. No space!
Has anybody else got a solution? I still see many of these little 2HP 2 strokes sitting on aft rails, so they're going strong yet.
After about 2 years of non- use in my father's shed before I decided to use the engine again, I extracted about half a cupful of congealed salty deposits from the exhaust manifold and cylinder block casting, before I could get water going through again. I really don't want to have to do that regularly on a pontoon or peir somewhere!
It might be possible to fit a 1/8 or 1/4 NPT fitting to the lower leg - and temporarily block the the original intake while feeding fresh water into the new fitting.

Solutions appreciated.

Graeme

 

[fmoran]

I bought mine in 2001 for £270 and decided on a no maintenance policy - just run until it died ( origional plug, no fresh water flush, etc ). Its used most weekends from April to October on my Avon tender ( now 22 years old ). Last year (2009) at the start of the season the Yam refused to start for the first time ever, was seized and could not pull the starter cord. I used lots of WD40 and a wheelie bin full of fresh water to free out and get running. In Oct 2009 I did put it in the wheelie bin of fresh water and flush before putting away and it started first time this season and running as good as ever.

Morale of story - just worry about flushing through with fresh water at end of the season and forget the hassle of doing weekly. Pity they don't still build engines like this any longer.

 

[Fantasie 19]

Much as I'd like to flush mine every time I use it, my Yamaha 4Hp 2 stroke lives on the boat so my experience is the same as fmoran's... it gets serviced at the start of the season, and flushed with fresh water at the end of the season... and that's it.. seems to be OK on it.

 

[electrosys]

If you were to remove the prop, then perhaps you could flush it in a bucket of water ?

Rainwater, or tap water if it's soft, is the best stuff to use.

 

[lw395]

If you were to remove the prop, then perhaps you could flush it in a bucket of water ?

Rainwater, or tap water if it's soft, is the best stuff to use.

That's what I do, every few weeks, seems ok so far.
Prop comes off with just a pair of pliers on the split pin, so no hassle.
I use warm water, dunno if it really helps dissolve the salt?

 

[pagoda]

That's what I do, every few weeks, seems ok so far.
Prop comes off with just a pair of pliers on the split pin, so no hassle.
I use warm water, dunno if it really helps dissolve the salt?

Thanks for the ideas,

I like the prop -off suggestion, nice & easy and a 2 gallon bucket will probably be OK for the job.

The idea of modifying the lower leg is now firmly off the agenda

Graeme

 

[VicS]

The idea of modifying the lower leg is now firmly off the agenda

Probably wise.

You would either have to make provision to screw a hose tail into a cavity in the lower unit between water intakes and pump or devise some way of connecting to the power head. You could not simply connect to the leg as that is not much more than a glorified exhaust pipe. The water passes up a small tube inside it.

 

[Fire99]

After doing a rebuild (which was no doubt a bit overkill), I did find that the waterways going to the cylinder head are pretty small on diddy outboards (2-3hp) so for that reason I flush mine through whenever there is an opportunity. (Fortunately the sailing club have a couple of drums for the purpose).

However I wouldn't lose too much sleep if I couldn't. My engine has survived periods where flushing wasn't an option and also, now I know how it works internally, if it did start playing up, It could be repaired in a couple of hours.

Those little 2-strokes are great little workhorses.

 

[dutyhog]

very forgiving

these engines are very forgiving. I flush ours only at the end of the season in the boatyard's outboard tank, then clean the plug and check the propeller. It always starts 1st or 2nd pull next spring, and seems to pump through enough water.

It dropped off the Avon one day (the bracket broke), still running under water for a while before I pulled it up on its rope. After quickly getting out the plug I flushed it dozens of times with WD40, and it restarted.

Gordon

 

[pagoda]

Probably wise.

You would either have to make provision to screw a hose tail into a cavity in the lower unit between water intakes and pump or devise some way of connecting to the power head. You could not simply connect to the leg as that is not much more than a glorified exhaust pipe. The water passes up a small tube inside it.

I've had the whole thing to pieces a couple of times- replacing the water tube as well as assorted seals / gaskets. That can be done with a decent Phillips screwdriver and a couple of 10mm sockets- on a pontoon on one occasion ;-) .
The torque settings for the M6 bolts on the cylinder casting are tiny, but I still don't like disturbing anything with small thread forms in fairly antique alloy.
It would have been easier to put a threaded connection into the flat "labyrinth" exhaust block under the powerhead- but that would have left the impeller almost certainly dry.
One split pin /prop off sounds THE way to do this.

thanks,
Graeme