info on johnson AD-10-M 7.5

[jimfj]

would like some info on a johnson 7.5 hp motor serial# 1435940 model# AD-10-M. How old? Is it collectable? What would I have to do to get it running. (the motor is in excellent shape and has spark. Put a little fuel in the cylinders and she fired. The "mile master" gas tank that came with it is gunked up a little so I didn't connect it.) Do I have to use this tank or can I get a late model tank and will it work?

 

[ob]

Re: info on johnson AD-10-M 7.5

Your motor is a 1956 model.Don't know of the value.There are a few buffs that are members of this site that can give you some insight as to the fuel tank question.

 

[jimfj]

Re: info on johnson AD-10-M 7.5

thank you for the year info! How did you come up with the year? Is it the model# or the serial # that tells you?

 

[ob]

Re: info on johnson AD-10-M 7.5

The model number.Here's a site that is not all in english but fairly easy to follow.Click on MODELLGUIDE in the upper right corner and then select a brand.HK is horsepower.<br />www.marinshopen.se

 

[alcan]

Re: info on johnson AD-10-M 7.5

Hi Jim <br />Your motor uses a presure type fuel system. There is no fuel pump to supply fuel. Most outboard fuel pumps are driven by presure pulses from the crankcase. In your case these pulses presurize the tank.In order to use a modern style tank you will have to convert to a fuel pump. This can be done. How ever it has been my expirence this pans out a wash or more expencive. In your case, since you already have the tank and hose,it would be more troble than it's worth. The easiest thing to do is disassemble your unit, clean it and install new gaskets and o-rings. This will give you a dependable system for the next 40 years (give or take). I like to think of these tanks as credit cards to inexpencive motors. As most of the time a good presure tank is worth more than the motors.

 

[jimfj]

Re: info on johnson AD-10-M 7.5

thank you to both! I appreciate your replies. Any suggestions for cleaning the tank and also where to get the seals and "o" rings. I am not sure how to get all the little rust particles out of the tank and should I use a fuel filter after all this is done, just in case I don't get everything perfectly spotless. Also what about the carb. Is there some way to flush the bowl without getting crud into the motor. Sorry for all the questions but I haven't worked with this kind of fuel system before.

 

[rickdb1boat]

Re: info on johnson AD-10-M 7.5

Hi jimfj<br /><br />A little more info on your motor<br /><br /> web page

 

[alcan]

Re: info on johnson AD-10-M 7.5

Hi Jim<br /> The first thing to is find the parts. Check your local dealer he should be able to help. If not there are tons of places to contact on line. As far as cleaning out the tank, disassemble it first, be carefull as there are some small parts and springs, note where they go. Then you can use what ever works from navel jelly and a modified toilet brush to some fancy acid product for cleaning motorcycle tanks, it's called Kareem or somthing. Just use the cleaning part, you won't need to do the sealing. (This is a two part kit). Of course try to do the best you can, but don't worry if not 100% perfect. Most guys tanks I see are about half full of crap anyway. The filter screen on the tank pick-up and the filter in the sediment bowl on the carb should be enough. Just check the sediment bowl every once in a while and empty it when needed. FYI most of the rust is on the inside top of the tank. The knarly goo in the bottom is usually rust colored shellac and oil. Usually looks and smells worse than it is.

 

[rickdb1boat]

Re: info on johnson AD-10-M 7.5

I've read on here about guys that use a box of BB's and some rubbing alcohol to clean their tanks. Just dump the BB's and Alcohol in the tank and shake it like crazy. Also have heard nut and bolts work too.

 

[jroberts24]

Re: info on johnson AD-10-M 7.5

Hi jimfj,<br /><br />I have a 1955 10hp seahorse. I am currently converting the fuel system. I have heard there is a kit for the conversion, but I have not found it yet. Also, OMC makes an external diaphram fuel pump that would probably work. They are good ole engines, but need a lot of care to keep them in good condition. Parts are becoming harder to come by and most outboard mechanics won't work on them. Therefore, you will need to purchase some service and owners manuals and prepare to work on them yourself. The old Johnson engines are definitly classics. If you take care of it,it will be a good conversation piece along with a good fishing motor.<br /><br />Good luck,<br />jroberts

 

[jimfj]

Re: info on johnson AD-10-M 7.5

thanks to all for the help! I am pretty sure the motor has sat around for a long time what about water pump issues. How hard is it to change the impeller? Any other tips for the first start up? Thanks again for all the help.<br /><br />Jim

 

[Chinewalker]

Re: info on johnson AD-10-M 7.5

Hi Jim,<br /> Not hard to replace the impeller, but you do have to pop the powerhead off to get at the shift rod disconnect. Be prepared to make a new powerhead to exhaust housing gasket.<br /> Be VERY careful with the springs/washers at top of driveshaft. Take note of the order in which they come off to assure they go back on the same way. There's a bakelite plastic piece that can be brittle, so care should be taken. Grease the driveshaft splines before reassembly.<br /> Impellers are available in many places - OMC dealers, NAPA, West Marine, etc...<br />- Scott

 

[ArneA]

Re: info on johnson AD-10-M 7.5

Another good thing to do is to disconnect the fuel line from the tank and the other end...I found that when cleaning my AD10M the fuel lines had quite a bit of crap in them...I took carb cleaner and blasted it through the fuel line until all the gunk came out.

For all you guys that have coached me for weeks. My AD10m has had the power head gone through and all new gaskets and a paint job. Just started priming the lower unit tonight but you know, I got to be a nut because it is in the mid 30's here and I have to bring parts in to the house and heat them by the wood stove, then hurry outside and spray a little before the metal turns ice cold, then back into the house to begin drying and curing. The wife is not too happy about the smell in the house...But,,,Life does have its priorities.

 

[nwcove]

Re: info on johnson AD-10-M 7.5

marineengine.com has almost all the parts you will need, or you can cross reference part numbers from sierra to napa. ( its as much fun tracking down parts as it is installing them! jmo)

 

[ultra353]

Re: info on johnson AD-10-M 7.5

2003 thread

 

[1946Zephyr]

Re: info on johnson AD-10-M 7.5

The motor must be worn out by now.

 

[I like old things]

I have a 1956 johnson 7.5, unfortunately I don't know how to use the gas tank. I understand you have to pump it up and fill the carb. But I don't know how many time you pump it, or if it just becomes hard to pump when its good.

 

[GA_Boater]

Why post in a 17 year old thread when you can start your own? We mostly ignore old threads except when the OP restarts the thread.

Closed.