dory 11ft and yamaha 9.9hp

[polotche]

Hi,
My name is Mathieu. I comme from France and I have a dell quay dory 11 FT with a yamaha 9.9 2stroke of 1983
When I go fishing, I think my boat is not fast
Is what the owners of the same boat thinks about my motor with this body??
Thanks a lot

And sorry for my bad english

 

[Sea Rider]

Welcome to Iboats,

Alternatives :

-Convert that 9.9 to a 15 HP, check which parts are needed for convertion.
-Go for a less pitch prop to pull wot revs up, will need an induction tach for that adventure.
-Or a combination of both.

Which is the current pitch stamped on prop body ?

Happy Boating

 

[polotche]

Thanks Sea rider for your answer.
To convert my yamaha, I must change the carburetor and the reed valve but I don't find this In France...
The last day, With my fisher friend, we naviguate at 6.8mph max

I don't now the pitch of my pro, I have to look

Thanks a lot

 

[Sea Rider]

You're welcome,

You can order those parts from a US outboard parts dealer and shipped to France along a prop. Much cheapper than buying a new or second hand 15 OB. Can look for those if you want. Will also need reed valve assy gaskets..

Happy Boating

 

[polotche]

Ok, but I m not sure what the parts are necessary to convert my yamaha??? I see and hear a lot of things

My motor is a short shaft but I don't known if it's adapted to my dory? I put it back



What is the price for the parts in your country??
Thanks

 

[QBhoy]

Hi
I'm pretty familiar with the dellquay dory you have. They are uk made boats and made by the famous Fletcher boat company.
Although these boats are heavily built with their cathedral hull, the 11ft and even the 13ft model has been known to plane with 2 people and anything from an 8hp up to around 35-40hp.
With your 9.9 two stroke and 2 people, it should get up on the plane with clever weight distribution and probably achieve around 15mph+
If your engine is running well and has a decent compression on both cylinders, I would imagine the prop isn't right, the weight distribution needs adjusting, the hull may be saturated with water (they are double skinned from memory and known to have water trapped in there from age and damage. Some people even drill a hole and put a bung in to drain the void space) or perhaps toe motor is a long shaft and not suited to the boat ?
Have a think about the above and let us know how you get on.

 

[polotche]

Hi,
ok thanks QBhoy
I see my prop and it's a 8or9 1/4 X 9 3/4

I don't known the cylinders compression

For the weights distribution, my friend is in the front and me in back but I'm modified the bench for to be more on the back

I hear for the water in the hull, but I have not hole in the hull. If I do a hole, what is the place to drill??

What do you think about my propeller?

Thanks a lot

 

[Sea Rider]

Why did you shimmed transom up in the first place ? it's a L shaft OB for a S transom height ? Forget all about AV plate talk, word of mouth that has to be even with lower keel/hull, says nothing as won't know at which lower leg height water flow at speed passes by when hull rises out of the water.



Lower leg sweet OB/transom height is when flow skims right under small upper water deflector plate (Yellow Line) at plane with OB sitting at 90? and well balanced deck weight (passengers). Visually check by pulling head over transom at which lower leg height is flow passing by.

If passing over yellow line will produce back/over water splashes rear of transom and will slow combo down, will need to rise OB on transom. If prop aerates around red line or over it at speed on choppy water cond or at tight close turns will need to lower OB down towards yellow line. The yellow line is the border between top boating and so-so one. Check this under a wot run and report your findings. Doesn't matter if OB is a S or L OB, as long it sits at a correct height while shimmed, with modified transom height or adding a transom mount to work spot-on. Will look for conversion parts and their cost...

Happy Boating

 

[polotche]

Ok many thanks Sea rider
My Yamaha is a short shaft





I will remove the holl and test with this setting this week

I think I understood
I hope to go faster like this...

 

[Sea Rider]

You're welcome,

Chech this video, try to match same exact lower leg height, flow passing unde upper plate...

https://www.youtube.com/watch?v=oBeZjaA76VM

Happy Boating

 

[QBhoy]

Hi
If it's a short shaft, it is ideal for the boat.
If she isn't planing, I'd say she is trimmed wrong of full of water.
All the best.

 

[polotche]

Hi,
ok, I will remove the hole and I would drill the hull

 

[QBhoy]

Before you do anything so drastic....take it out the water and listen for water inside it first. You will be able to tell.

 

[Sea Rider]

If boat sits well secured on a trailer just bounce Bow/Transom up/down, if there'e water running inside hull should hear it, if the inside foam is just wet, that's another story. Or take the combo to a weight scale to have it weight, must know the boat weight when factory delivered...

What's the exact 9,9 model letter attached to it, say 9.9 ELN, ESN, LK, LN ? Is there a labeL attached somewhere. Check as model is all when looking for spare parts..

Happy Boating

 

[polotche]

I will try to ear if there is water in the hull

For the motor, I don't see anything so I don't known the exactely model...

 

[QBhoy]

There will be a metal plate with model number etc on the main bracket that attaches to the boat.

 

[polotche]

Yes I have this plate on the boat but we talk about the motor and I don t known what is th? exactly model...

 

[Sea Rider]

Boat's plate is somewhat irrelevant as you can dial an OB to rev to it's max wot rpm range with a correct prop but not at a wow speed if being extremely under powered while lightly loaded. What's the current number stamped on prop body, blade, whatever ? Currently checking parts for the conversion....

How healthy is that oldie OB, has few run hours, was extremely used, is mint cond. Asking this because the conversion is not a cheap one, but not a costly one too. But if don't plan changing it for a modern newer OB, could be the way to go...

Happy Boating

 

[Sea Rider]

There's a great wot rpm difference between a 8 and a 9 pitch prop, check exactly what OB is running with ?

Happy Boating

 

[polotche]

Hi
I looked again my propeller and I am now sure that is a 9 1/4 X 9 3/4

The propeller is damaged, look the picture

I don't change my engine right away, so I think I will buy a new propeller



Thanks a lot