1959 Johnson 9.9 outboard

[Lt. Holden]

Originally Posted by mydauphin

I also have 15hp Evinrude which is same 9.9 hp with a different carb I believe. It is an excellent motor once you upgrade to single line, 50:1 mix. Lots of power runs great. Unbreakable.

I currently have a 1960 Evinrude Sportwin 10 HP on a 12' 1960 Alumacraft Vee puddle jumper. It runs great but the boat is a tad too small for two guys to fish from (imho). I have a 13'6" flat bottom dinghy hull that I would like to restore. I don't think the 10 HP will be quite enough power; I would like 20 mph or so.

Can anyone clarify on the differences between the 10 (or 9.9) and the 15 HP? If I could simply buy a carb and get 5 more HP that would be great.

[Lt. Holden]

Originally Posted by mydauphin

By the the way, I also have 15hp Evinrude which is same 9.9 hp with a different carb I believe. It is an excellent motor once you upgrade to single line, 50:1 mix. Lots of power runs great. Unbreakable. The two stroke is much lighter per hp than 4 stroke.

Can anyone clarify that this is correct? I have a 1960 Evinrude Sportwin 10 HP that runs great. I want to swap it from a 1960 Alumacraft 12' semi-vee to a 13'6" flat bottom dinghy that somebody left in my yard. If simply swapping the carb gets me 5 HP that would be way cool .

Sorry for the double post. it didn't look like it posted the first time, can I delete one of them?

[thudpucker]

Better post a photo Lt. I never heard of a Flat bottom Dingy before.

They only way you could know for sure is to see a parts list for both engines. If the only difference in part numbers was the Carb and Reed block, then it will probably work.

[mydauphin]

Originally Posted by Lt. Holden

Can anyone clarify that this is correct? I have a 1960 Evinrude Sportwin 10 HP that runs great. I want to swap it from a 1960 Alumacraft 12' semi-vee to a 13'6" flat bottom dinghy that somebody left in my yard. If simply swapping the carb gets me 5 HP that would be way cool .

Sorry for the double post. it didn't look like it posted the first time, can I delete one of them?

Yes, search on internet, there is even a video how to do it on utube

[ondarvr]

Its not a good idea to run the older 24-1 engines at 50-1, the older engines use bushings that require more oil for lubrication, the newer engines have needle bearings which require less oil. The change on oil ratio was made in the mid 60's when J/E went to all needle bearing designs. J/E recommended 100-1 for a couple of years on some small engines, but changed back to 50-1 after storage problems at 100-1 (not enough oil to protect from corrosion when left sitting).

The conversion to a fuel pump and single line tank allows you to use the newer, more common and lower cost fuel lines and tanks, but doesn't really change anything else.

The J/E models out of the 50s have a following because they were simple, easy to work on, parts are still available, reliable and sort of low in cost.

[ondarvr]

The switch from 9.9 to 15Hp is one everybody asks about. There were a couple years that the only part difference listed was the carb (in the 70's I think), after that it was the carb and other parts, you need to get a parts breakdown for each model year to find the differences. Many people complained there was very little difference in power between the two when new, so the swap may not gain much. Since everybody wants the 15hp parts for the swap, they go for more money on ebay and at times are a difficult to find. Its much easier and normally costs less to sell what you have and buy the one you want.

[thudpucker]

On two river in Alaska, people used hi-horspower jet boats to get up river, then drift down.
The wake damage was bad enough that Fish n' Game put a horspower limit of 35 on the river.
J/E Came out with the 35 Hp Alaskan. Immediatly the Rumor was; "The Alaskan was a 55 Hp engine with a 35 Hp Carb on it!"
I dont know the truth, but it seems pretty similar to the 9 to 15 Hp rumor.

Thanks for the Explanation ondvar.

[ondarvr]

The Alaskan 35hp rule made things difficult and actually worse for the shoreline. Instead of being able to use a higher HP engine that would fully plane the boat when it was loaded, they required the lower HP to reduce speed, which increases the size of the wake and results in more damage. They recenlty increased the allowed HP to 50.

The kits to detune larger motors to 35HP were installed, approved and then later modified to defeat some of the HP reduction. If you got busted there was a fine.

[thudpucker]

I was one (of hundreds) who went to the fish n' game meetings and complained about that very thing. A boat moving slow makes a bigger wake.
I had already left when the changed the rule. I didnt know. Thanks.

[Wynand N]

Originally Posted by ondarvr

The switch from 9.9 to 15Hp is one everybody asks about.

Most manufacturers having these two motors use the same "de-powering" techniques from the 15 to 9.9hp. The obvious difference between them are the RPM where the said HP is achieved and some carb tuning. All 15's runs about 500 RPM faster than the 9.9's. Both these motors have the same engine displacement and weight.

Tohatsu make things actually worse or better perhaps. They not only have a 9.9hp, but also a 9.8hp and as a dealer in these engines I usually recommends the 9.8 over the 9.9. The 9.8 is a totally different motor than the 9.9 with a smaller engine displacement and weighs 15kg (33lbs) less than the 9.9! giving it much more bang for weight and cost considerably less than its fractionally bigger brother....

[thudpucker]

Interesting. Sounds like Tahatsu bought another company's motor for one or the other dont it?

At any rate, in the 60's, Tahatsu was the first Jap importer of a Motorcycle that looked like a Motorcycle. Good little unit.

[spare parts]

I am currnetly using a 1956 johnson 5.5 to push my 20 foot sail boat around the ocean with and i can tell you from days and weeks of on the water experience it doenst polute any worse than any of those huge gas guzzling V8s and sixes ive seen getting off at the boat ramps.
Just mix the fuel right and use the righht oil WHICH by the wayGonzo ..Isnt 30 weight oil.

[powerabout]

did anyone mention there wasnt a 9.9HP till 1974!
There was a 15 in 56 but then none till 74

[thudpucker]

The (censored) in CA put up a law limiting engines to 9.9 Hp on lakes. That was the year all the engine makers came up with a 9.9. CA markets are huge.

My brother has a 20' Sail boat with a 10 Hp Honda. He goes up n' down the Columbia with no problems. Quiet and moves along about Six mph or more sometimes. I enjoyed those rides.

[spare parts]

I have a 1954 johnson cd 10 5.5 horse i woulndt trade for the newest of any available outyboards on the market today. it runs cleans and fire evry single time on the first pull! gets excellent fuel mileage,and parts are still cheap because the parts are off the shelt and not some dang propritery piece of over priced junk.