dory engine shaft length

[Jaco]

Hi,
I have just bought a 13ft dell quay dory and 40hp Mariner 1984 engine.
When out at the weekend on the river i tried to open up the throttle and found i had very little power - we were only able to do about 15mph - the engine was also changing pitch as if struggling.....

I noticed that the cavitation plate was in full view with the power on and on our return to the boat park took a look at the set up.

The cavitation plate was approx 3inches above the bottom of the hull.
On reading articles online, would it be fair to say that the engine is a short shaft model and i need a long shaft module?

My solution is to cut down the transom by approx 3 inches to get the Cavitation plate level with the hull.

I am hoping changing the fuel and correcting them mix may help the power also?
Any help or advice would be appreciated!
Cheers
David

 

[WF36]

You dont happen to have a picture of the back of the boat with the engine down do you?

( A picture says a thousand words!)

Will

 

[Jaco]

Hi will - good idea - I will take a picture this evening.
thanks
David

 

[Dave_Seager]

I have an 11' Dell Quay Dory. It is kept on a quiet, inland river and I normally use a Minn Kota electric outboard. However, I have tried a couple of small, standard shaft outboards on it and they are definitely too short and unusable. I have concluded that it does need a long shaft. (The Minn Kota has a long shaft but can be set to almost any depth.)

I would be reluctant to cut down the transom on a dory if you plan to use it at sea as it would reduce the freeboard and might compromise the safety of the boat.

 

[VicS]

The cavitation plate above the prop should be in line with the bottom of the transom or up to about 1" lower

See www.smalloutboards.com/shaft.htm

If you have a standard aka short shaft engine and the cavitation plate is several inches above the bottom of the transom then then you clearly need a long shaft model.

Depending upon the engine model it may be possible to convert it to a long shaft.

Butchering the boat is another option I suppose.

As it is you run the risk of losing proper cooling water flow leading to overheating quite apart from not driving the boat properly.

It should all be explained in the owners manual anyway.

If you have mislaid your copy the you can down load one from HERE.

RTFM as they say

 

[3663Ian]

I have a old Dell Quay 13 with a 40hp short shaft Mariner. The older DQ13s had deeper cuts in transom for a short shaft engine. The newer ones don't have the cut out in the transom and need a long shaft.

I can compare your picture to mine when you post it.

 

[Jaco]

outboard engine shaft length on a 14ft dory....

Hello All,
I have attached 3 pictures of the outboard and transom - as i said it looks like the cavitation plate is about 3 inches above the bottom of the transom.
Think I am going to have to locally cut it down by at least that bearing in mind the turning lock will make the engine clash with the transom......

make sense?
thanks
David

 

[northwind]

The shaft on the engine is too short.. you need a long shaft engine. Or you need to lower the engine mount.

 

[VicS]

+1
You need a long shaft engine!

See the link in my earlier post .

 

[Jaco]

yes thought as much - are there any major problems/issues with cutting and re-glassing a section of the transom?
thanks!

 

[VicS]

You will be compromising the safety of the boat by reducing the freeboard.

You may well also invalidate your insurance

 

[3663Ian]

I just checked mine....With a short shaft engine the plate lines up exactly to the bottom of the hull as Vic suggests. This is due to the deeper tansom cutout on the older Dell Quay Dorys.

Personally I wouldn't fancy cutting the transom of good boat. If it was mine I would try to get hold of a dead outboard of the same type with a long shaft and swap the parts over. If I remember correctly there is a seperate part to extend the leg.

I am sure someone can advise what is needed.

 

[VicS]

I am sure someone can advise what is needed.

Without knowing precise model details it is not possible to say exactly what will be required but as far as I can see it will be

Drive shaft housing , drive shaft, lower shift rod ( shift cam) and water tube

Possibly some other minor bits and pieces that I have not spotted.

So if one can get a dead long shaft you might as well swap the whole leg complete if its OK

 

[greenalien]

Might just be less hassle all round if you sell the engine and buy a long-shaft model...

 

[WF36]

Might just be less hassle all round if you sell the engine and buy a long-shaft model...

+1

Long shaft definatly needed - after seeing the pictures.

 

[chi-girl]

if it were me i'd change the engine and leave the trasom original.

i think you'd be better to invest the money you would spend on a transom rebuild and get a newer and longer outboard.