1955 johnson 15 and 18 difference

[warrenjets]

So... I was doing some digging. I have a 15hp johnson and its a 1955. I was wondering if there is a huge difference between it and a 18hp johnson??? I would be nice to get some more ponies out of her. Thanks. Jake

 

[HighTrim]

Re: 1955 johnson 15 and 18 difference

THe 18 does have more oomph, but there is no real quick/easy way to upgrade your 15 other than simply get an 18.

I love the 18hps from the 50s, pound for pound they are awesome.

 

[JB]

Re: 1955 johnson 15 and 18 difference

There was no 15 in 1955, WJ.

Your outboard must be a FD-10, a 1956 model. It was 19.94 CI. For 1957 the FD series was bumped up to 22CI. in the 18HP FD-11.

There are probably other differences beside the displacement, but the bottom line is that a FD-10 cannot be converted to a FD-11.

 

[HighTrim]

Re: 1955 johnson 15 and 18 difference

Didnt even catch that JB!

They did have an Evinrude, maybe some sort of Frankenrude. What is your model number WJ, or a pic?

 

[Pheroo27]

Re: 1955 johnson 15 and 18 difference

Maybe someone can help me. I have an older johnson that I believe to be an 18hp. The model number is FD15F. Need to know how to adjust the two knobs on the front of the motor.

 

[HighTrim]

Re: 1955 johnson 15 and 18 difference

Maybe someone can help me. I have an older johnson that I believe to be an 18hp. The model number is FD15F. Need to know how to adjust the two knobs on the front of the motor.

Indeed a 1961 18hp, start a new thread so that we dont get confused, it happens alot, lol

You will get plenty of help adjusting the needles, or look in the FAQS for a thread by Joe Reeves that covers it.

Here it is here

http://forums.iboats.com/showthread.php?t=167352

Good luck

 

[1946Zephyr]

Re: 1955 johnson 15 and 18 difference

Maybe someone can help me. I have an older johnson that I believe to be an 18hp. The model number is FD15F. Need to know how to adjust the two knobs on the front of the motor.

You might be best off starting a new thread, versus hijacking an exhisting one. The high speed (bottom is about 3/4 turn out and the low speed (top) is 1 1/2 turns out.

 

[1946Zephyr]

Re: 1955 johnson 15 and 18 difference

So... I was doing some digging. I have a 15hp johnson and its a 1955. I was wondering if there is a huge difference between it and a 18hp johnson??? I would be nice to get some more ponies out of her. Thanks. Jake

The 15's were originally built by Evinrude from '53 on to '56. Excellent improvement over the 14's of 1950 and 51. Johnson and Evinrude totally combined their product line in 1956 and the 15 was available in the Johnson marque, as well. The FD/Fastwin was even more improved in 1957 as an 18. This 22 cube design was actually the base design for two more models up until 1976. The 20hp of 1966 and the 25hp of 1969. One of the best designs ever built by OMC. An 18hp powerhead should mount on the 15 midsection though and work fine, since this part was the same, from 1956 - 58

 

[Shane7]

Re: 1955 johnson 15 and 18 difference

An 18hp powerhead should mount on the 15 midsection though and work fine, since this part was the same, from 1956 - 58

no it will not I tried it and the water passages are different it will bolt on but won't pump water this caused me a lot of trouble trying to find out why it wouldn't pump water if you use a 18hp midsection it will work though