What's this johnnyrude worth?

I'm looking at possibly acquiring a 9.9 motor for use on HP restricted water. I have a potential motor but I'm not sure it's worth it. The owner says he got it in a boat deal but already had a bigger motor he used with the boat. He's had it sitting in his shed for 3 years and thinks it's a 76-78 model. He thinks the PO told him it had a 15hp carb on it. I'm pretty sure the "blue" motor is an evinrude with a johnson 9.9 cover (pull start only). It's missing the slow speed adjustment knob and all of the silencer assembly from the carb. It's pretty dirty and has a little rust under the cover but looks complete otherwise. I've never owned a johnnyrude before, so what's the verdict of all you experienced johnnyrude owers? What would you pay knowing you may have to resort to parting it out just to get your money back? Of course all this is would be based on it passing an onsite inspection and compression test.

Missing parts, not running, carb rebuild, water pump, seals and gaskets, and whatever else you find in the process. $100, but I'm so cheap, I squeek. If you can get the model number and a picture, ask at AOMCI.org. Those guys will know for sure.

Check the compression in both cylinders. If there over 100 psi and within 10% of each other it's a good motor. everything else can be fixed.

Some very important differences between the 76 and 78 also. Well worth having the 78 if that is what it is.

Thanks for the replies. I've got some pics in facebook PM, not sure how they'll look from a copy/paste but I'll check. I've got him looking for the Model/serial now. Do any of you happen to know where the plate is on those year models? And I must be cheap too ggoldy, because that's the first number that popped into my head when I got the pics of it. :lol:

The ID plate is on the side of the transom clamp.

crazymanme2 said:

The ID plate is on the side of the transom clamp.

Click to expand...

Thank you.

Only difference between a 9.9 and a 15 HP is the carb jets. Not running and missing parts I wouldn't spend more than $100

Only difference between a 9.9 and a 15 HP is the carb jets.

Click to expand...

False.

The throat is larger on the 15hp carb to flow more air.

bobby_r67 said:

Only difference between a 9.9 and a 15 HP is the carb jets. Not running and missing parts I wouldn't spend more than $100

Click to expand...

I was under the impression that there was something different about the exhaust also, but as I stated earlier, I've never owned one so I'm only going by things I seem to remember reading somewhere.

The early ones had the same exhaust, but I believe in 79 or 80 the exhaust was different on the 15.

70s exhaust all the same, square-tube type.

Early to late 80s had a megaphone/expansion-chamber type exhaust on the 15hp...square-tube on the 9.9.
OUTER housings were different too.

Late 80s on up, all had the same 15hp exhaust system.

Some of the 80s 9.9 'sail' versions have the big 15 carb but the jet is a little smaller than the 15hp jet. (54jet instead of a 56jet). That's because the sail versions don't have the megaphone exhaust. The 15hp with the megaphones ran up to 7000rpm and needed the extra fuel. The sail versions never ran that RPM at full throttle.

By the way, I tried putting a 40hp jet in a 30hp Merc once. That's how I know for sure it won't work. Soon as I opened the throttle it started choking on fuel. Looking through both carbs I discovered why. The 40hp carb was much bigger. Can't tell ANY of that from the parts book.

If I don't have someone else's mistake to learn from, I have to make my own.