Modifications - a good idea or not?

[daydreamingdave]

Hi all,
Last year I purchased a model 90. Against all the advise I bought it sight unseen off eBay. I am in Ireland and the 'gull was in Poole.

The model number is EFNR 564FF9

Well a house move, a broken leg and a year later I unwrapped it, checked it over and started it. All good. The cap on the tank says 10:1, so I dont think that is original. The prop is a 4 leaf clover type and the gearbox has three screws holding the cover on.

The carb is on the starboard side and the tiller arm is on the port side. I have no idea if this is the right setup.

What I want to do is fit it to my 17 ft wooden open fishing boat. To get the prop in the best place, so it pulls clear water I will need to extend the leg by 9 inches.

Is this a mad thing to do?

I have no problem with physically doing it. I also plan to add water injection into the exhaust tube.

Will the back pressure be too great?

Lastly, is this the right prop?


Any ideas are welcome!

Thank you,

David

[Charles uk]

Does the prop have an internal or external spring?

A picture of the prop & a couple of pictures of both sides of the whole motor would enable us to give accurate answers.

[thcl500j6]

This is what the longshaft version looks like

This is a Tasmanian engine thats why the pictures are upside down, its
"Downunder" its i a lot better condition now.

This was the engine Adrian found for me.

[daydreamingdave]

The prop spring is inside the prop.

What I am after is thrust. Is there a better prop or is this the thrustiest?

[daydreamingdave]

Some more pics

[Nudge]

Take another pic showing us the motor in the down position on the back of the boat and indicate where the water line on the boat is.

Is it a case of not having enough thrust or is it more speed that you are really after?
Is the boat being used in salt or fresh water? If it is salt what is the tidal flow like?

[daydreamingdave]

It is thrust I am after. It is a displacement Hull so speed is not an issue.
Fresh water on Lough Ree in Ireland. The river flow could be up to 4 or 5 knots I suspect.

I will post a pic of it in the down position tomorrow, and you will see why I need it lowered.

[daydreamingdave]

As you can see the motor is a bit high. The idea is to place the prop behind the lower part of the Y transom so it pulls clear water.
If I extend it by 9” it will do the trick. That way the Skeg on the gearbox is just above the keel line.
I may need to do something to reduce back pressure.
I am planning to inject the water into the exhaust pipe but I may also drill a hole just below the new waterline.

[thcl500j6]

Hi if you were in Australia i would offer to swap you a long shaft motor for yours, and you'd be sweet. try mounting the motor off center, and see how you go, that will give you clear water flow under the hull, for the motor, fishermen have been doing it for years.

britishseagull-boat.jpg (10.35 KiB) Viewed 4898 times

Sorry i didn't have a picture of the EFNRL on the boat.

[Nudge]

Hi if you were in Australia i would offer to swap you a long shaft motor for yours

I will do a swap as long as he pays the shipping both ways from New Zealand!

If you can try a transom bracket before you change the motor.... once you have cut it, you have cut it and there is no going back!

[daydreamingdave]

Not sure putting it off center will do the job.

Not planning to cut things, but to make new, longer extensions. I can always put the original back together.

It’s more about keeping the bottom end in the water when I am standing midshipmen or up front.

[roxylass]

Get a transom bracket it will drop your engine a good foot

[daydreamingdave]

Well, I have eventually got around to getting the extention sorted. I have discovered that the exhaust port is bulging and there is a crack in the block. It is also very corroded and full of rust. Add to that the fact that I broke two head bolts means that this block is free to a good home!
So I have sourced a replacement.
The big question is if I should hone the bore and fit new rings, or leave as it is? Maybe replace the rings, maybe just hone the bore?

I do not know what the compression was when I started, but it ran well.

The piston and rings seem in good condition.

This is as far as i am going at this stage. I could strip the gearbox but to what end? I was working fine and i dont want to risk shearing off any more bolts.

I have new parts and seals coming from John and all the individual parts have been cleaned and repainted.

So this is the last part of the strip down - apart from the carb, but that is not a big issue.

I read somewhere you can get up to 30% more power with new rings, and if fitting those it seems sensible to hone the bore. All or nothing I think!

[Charles uk]

I don't know where you read the 30% thing, new rings might take your compression from 50 to 55lbs if your very lucky!

Just fit your new cylinder & measure the compression before you spend too much more money.

[croweater]

Here is what I did to my dinghy, I offset the motor and cut down the transom works a treat. I am able to run either short or long shaft motors.
John