Johnson Seahorse 5.5 or 7.5??

[stilltrying]

I bought a used Johnson Seahorse a couple days ago and was in the process of getting some information and tuning it up. The motor cover says 5.5 but when I checked the model number on the side to cross reference the year I noticed the model # is AD-11. Which in my view means it is an 7.5 with a 5.5 motor cover? The serial number is 1562233.

I noticed when looking for pics that most of the 7.5 have a white handle but mine has a black...Is there any other markings that can differentiate? Also does it really matter? I ordered a carb kit and it has the same part number. Are the plugs the same? Any info would be great.

 

[HighTrim]

Re: Johnson Seahorse 5.5 or 7.5??

By model and serial number it is a 1957 7.5hp.

Could you post a pic so we can pinpoint what is what?

 

[bbstacker1]

Re: Johnson Seahorse 5.5 or 7.5??

As HighTrim said, by model number it should be a 7.5, either way you have a nice little motor. Carb kit, plugs and impeller or foot reseal kit, if needed, are the same between the two. The powerhead base gasket is different so you want to make sure you have the right one if you have to pull the powerhead. For an AD-11 the original tiller grip should have been white but many different years and styles will fit so a swap is very easy to do. A couple of pictures will go a long way toward confirming what you have, in particular one of each side of the powerhead with the cowl (hood) off, enjoy.

 

[nwcove]

Re: Johnson Seahorse 5.5 or 7.5??

i dont thhink the cowl from a 5.5 will fit a 7.5, but the transom clamp will.

 

[HighTrim]

Re: Johnson Seahorse 5.5 or 7.5??

Correct the 5.5 and 7.5 cowls are different.

SO.....Im guessing its a 5.5hp with an AD steering assembly?? The powerhead is easy, if the bypass covers are removable, it is a 7.5, but by the cowl Im guessing they are not. UNLESS, the decals are for a 5.5 on a 7.5 cowl? Sleeper?

 

[nwcove]

Re: Johnson Seahorse 5.5 or 7.5??

hmmm....sleeper? interesting thought! who knows, maybe there is/was a lake somewhere with a 6hp limit? hope the op posts pics.

 

[seahorse5]

Re: Johnson Seahorse 5.5 or 7.5??

I Are the plugs the same? Any info would be great.

Plugs are the same, Champion J6C, Mix the gas and oil 24:1

The 5.5 powerhead has a flat stampled aluminum plate over the exhaust ports, the 7.5 has a curved cast exhaust piece.

These were known to throw rods if overrevved from worn down props or revving too high in neutral as they were aluminum with brass bushings.

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

Plugs are the same, Champion J6C, Mix the gas and oil 24:1

The 5.5 powerhead has a flat stampled aluminum plate over the exhaust ports, the 7.5 has a curved cast exhaust piece.

These were known to throw rods if overrevved from worn down props or revving too high in neutral as they were aluminum with brass bushings.

I will upload a couple more. The carb is already off.

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

 

[HighTrim]

Re: Johnson Seahorse 5.5 or 7.5??

That is a 5.5 hp

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

Thanks! Now I know..

 

[HighTrim]

Re: Johnson Seahorse 5.5 or 7.5??

Still curious about the leg though, any pics of that? Did you get the model number from the tag on the leg?

 

[kfa4303]

Re: Johnson Seahorse 5.5 or 7.5??

Here are some handy links.

http://www.outboard-boat-motor-repa...ohnson 5.5 HP 1954-1964 Tune-Up Procedure.htm

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/377018/37701800001.htm

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

Still curious about the leg though, any pics of that? Did you get the model number from the tag on the leg?

I did get teh model number from the tag on the leg. I don't have a picture of the entire leg but will take one tonight and send.

 

[1946Zephyr]

Re: Johnson Seahorse 5.5 or 7.5??

Actually, the fuel mix is 16:1. One quart of oil, to 4 gallons. 24:1 is okay, but 16:1 is actually recemended for all OMC's under 10hp in the 50's

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

Here are some handy links.

http://www.outboard-boat-motor-repa...ohnson 5.5 HP 1954-1964 Tune-Up Procedure.htm

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/377018/37701800001.htm

Put carb kit in tonight and changed lower unit oil. Fired her up and set the low speed in a bucket. It prrrs like a kitten. Felt the head after idling for a while. It wasn't overly hot to the touch. Might try a on water test tomorrow.

 

[bbstacker1]

Re: Johnson Seahorse 5.5 or 7.5??

Stilltrying, since the motor is new to you and you don't know when it last had a new impeller that is one thing I would highly recommend doing before you do much running with it. On that engine you will have to pull the powerhead to change it but that is not really a big deal (if you can do the carb kit you can do this).

 

[stilltrying]

Re: Johnson Seahorse 5.5 or 7.5??

The previous owner said he ran it 4 years ago. That being said, you are probably right on the impeller replacement.

 

[kbait]

Re: Johnson Seahorse 5.5 or 7.5??

I had a cd-11 with an ad-11 tag come through awhile ago. I think they just grabbed the tag from the wrong bin, as the transom bracket was obviously original..

Maybe it was tagged after a liquid lunch at the omc factory