long shaft vs short shaft

[markle]

Hi all

just looking for some advice from salty old seadogs!

I have been playing with my seagull(s) for some time, one is a runner the other os a 'long term' project!

In the meantime I have aquired a short shaft 4hp evinrude, I hear you all curse!

I have blown the head gasket on it through overheating, and am wondering if it is not long enough ...

I bought the boat knowing it takes a standard shaft, but as time goes on there seems to only be short or long - with some calling short standard.

Could anyone advise on what the score is with this, are there short, standard and long, or just short (aka standard) and long?

I may just need a new impellor but being mr cheapo I dont want to spend out if its going to happen again, it reaches the water OK, but I wonder if it struggles to draw in water due to turbulance which would not affect a long shaft (have toyed with the idea of making some sort of hose pipe based tube to allow the engine to draw water up from the deeps straight to the impellor ...

Everytime the gasket went it was on the boat, seemed to run fine in the test tank, but it doesnt have much load in there so perhaps not much of a yardstick!

Any advice appreciated

Mark

[Keith.P]

This may help. http://www.smalloutboards.com/shaft.htm
And try a new impeller.

[markle]

cool thanks. I had viewed that site and it helped raise my question, long and short, or long short and standard?

and guess i will spend the £4 and indulge myself in a new impellor

it looks like it is brand new .... ouch guess i will take the hit on that one then!

cheers for the reply

Mark

[Vic]

Johnson and Evinrude use the term "standard shaft" rather than "short shaft". Off hand I cannot think of another manufacturer using the term standard shaft. Mercury/ Mariner call them short shaft as do all the far eastern manufacturers AFAIK

Nominally short/standard shafts are for a transom height of 15" . Long shafts for a transom height of 20" ( Extra long, 25")

Honda seem to measure their engines slightly differently.

None of the 4 hp Evinrudes has a cooling water telltale as far as I know so make sure you are getting some water blown out of the exhaust relief hole(s) on the back of the leg. It may only be a few drops or a mist. Be sure you can touch any part of the power head with the exception of the cylinder head around the plugs and the exhaust manifold cover and maintain contact for a couple of seconds or so. Steam from the relief holes is a bad sign.
If it has not been replaced recently renew the water pump impeller.

The older Evinrude 4 hp engines are reckoned to be just about the best outboard engine ever produced!

[chris]

I own a 4hp evinrude lite twin a 1972 model,
as well as all the seagulls
the evinrude is very quiet smooth and economical, but what I like about the seagull if anything goes wrong with it when you are out there it can normally be fixed.
with the impeller on the evinrude should you replace the housing as well?

[Collector Inspector]

Well, for what it is worth, this board is cool!

http://www.marineengine.com/boat-forum/ ... 777db&f=26

If you join them, do not mention ME! I seem to confuse when I post stuff. (Americans are kinda precious...............)



B

[Vic]

Well, for what it is worth, this board is cool!
http://www.marineengine.com/boat-forum/ ... 777db&f=26
If you join them, do not mention ME! I seem to confuse when I post stuff. (Americans are kinda precious...............)

B

The Marine Engine forum is not bad but not a patch on the iBoats forums. For Johnson and Evinrude http://forums.iboats.com/forumdisplay.php?f=24

.

[Vic]

I own a 4hp evinrude lite twin a 1972 model,

with the impeller on the evinrude should you replace the housing as well?

If it is worn yes but otherwise at the price ($86 US OEM price) you wont be wanting to.

An after-market overhaul kit may be available .. I have not checked.

[Collector Inspector]

Hmmm, I might have been somewhat "Down Under" for them as well in the past..................Maybe, maybe, just Me?

[Keith.P]

Iboats is a good site for info, but you have to put up with some blunt reply's. It does not matter how right you are, you will be wrong.
Info from people who collect manuals not outboards.

[markle]

thanks all for the replies, so I hope the motor fits the boat ... and will invest in a new gasket and impellor and see where I get to.

Really helpful stuff posted here

Not so bothered if the car packs in, but the boat can be a bit hairy!

Lucky I have the trusty ol' gull stashed away just in case ....

Tides on the river Tamar can run pretty hard and not the best place to be in a little boat with no power

Thanks again

Mark

oh and just one more ... how can I actually tell if the impellor has had it, it looks good as new? Is it something that looks alone can not confirm?

[Horsley-Anarak]

The kit I have looks like this

Water pump.jpg (175.07 KiB) Viewed 3744 times

The Impellor on the right has had some use, but the one on the left is new.

I have read that if there is little wear to the vanes then just reuse but the other way round.

The Johnson/Evinrude 4HP is a nice engine.
H-A

[Collector Inspector]

Another way to tell, which I have been using for ever is bend the blades backwards from the curved set each one. Do this when the impellor is dry and you have your specs on....well me anyway, going the post 45 close-ups.

Bend them really hard and note if there is any cracking or splitting of the rubber. If looks dodgy, throw away.

Yeh, if still OK this way and you need to reverse go ahead.

Wear on the side where it contacts the pump housing should be noted as if dodgy, this will stop 100% performance at idle or trolling revs.

Else, reuse and check everynow and again untill you are unhappy then replace.

B

[rosbullterier]

Markle - I've desperately rowed out of the midstream current (with one oar) in the raging Tamar to cling onto reeds by the river bank - while testing bloody Seagulls . . .

As I look out of my window - there is the Tamar. And on the other bank, Devon.

Where is your boat parked?

[markle]

Thanks for the impellor tips

Going to bite the bullet and go for the new parts, none of which are particularly costly even the housing.

And as for the Tamar tide, know that feeling, last head gasket failure was on a huge spring tide, launched convinced all was well from saltash slip - what an amazing facility for free! zoomed off under the bridge right in the middle of the river to keep out of the way of the moorings. Motor began to slow and soon I was travelling in an arc, then that was that, sideays back up the river

An anchor and old seagull got me out of that one, until I ran out of feul ... damn those seagull taps. Then it was the one oar trick back in, made it eventually though

I keep my boat in Plymouth, just a little 13 foot fishing boat, gunnels are a little low for my liking but I guess it keeps it looking the part (looks like an old Plymouth Pilot)

Would be fine if it were not for the speed boats charging past with their huge wakes ... nouveau riche I say (along with other words that start with f).

Thanks again

Mark