Johnson 9.9 Advice needed

[ocbinva]

Does anyone have any advice on a good book or web page regarding the restoration of the Johnson 9.9 from the late 80s. I was given one for free and the guy said it ran when he stored it but that was he said at least a decade ago. I just want to figure out what minimum steps I need to take to ensure I don't ruin it while trying to start it or a way to evaluate it to see if it's worth any effort whatsoever. I have restored many vintage vehicles and motorcycles over the years but I have no experience with OBs. Off the top of my head I can think about cleaning the carburetor, replace rubber hoses, replace impeller, and all fluids and grease. Any insight is appreciated.

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[CedarRiverScooter]

The 1st thing I would do is a compression test. If it has bad compression, it probably isn't worth all the cost to do a powerhead rebuild.

No need to get it started, just do it cold. Squirt some 2 cycle oil in, just to give it the benefit of the doubt.

If that is good, a water pump impeller, points, carb needle/seat/float, & fuel pump diaphram would not be wasted money.

Check lower unit oil for water intrusion too, worn seal is common.

 

[ocbinva]

Geez...duh... Guess its early. Not sure how i missed that since i always check compression on all old engines before i commit to a new build. My idiot gene is hard to hid with anything less than 3 cups of coffee. Happen to know what a good working pressure would be?

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[Johnny]

since i always check compression on all old engines before i commit to a new build

what guidelines have you used in the past ?





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[ocbinva]

Well depends. Most older bikes can be good at anything between 105 to 145-150. However a bike a worked on a month ago (Victory) with a buddy had a compression maximum value of 210 with a minimum acceptable value of 175ish. I figure I need to download the manual to see if it is identified for this motor. Since it was free I can put some into it. I work in a cube all day so they way I maintain my sanity is getting greasy on the weekends.

 

[Pappy]

Your engine does not have "points" as stated above nor is it common to seal wear or failure in the lower unit. Not that it cannot happen.
DO check the gear oil and change it with the impeller job. Common numbers for compression on that engine is near 120.
If a carb job is needed then get an OEM kit and do it properly, using all parts provided. The OEM kit is the only kit that comes complete with all parts needed. Aftermarket kits are not complete.

 

[wmk0002]

The factory service manuals can be had for about $20 on Ebay and are very informative in my opinion. Many model years are exactly the same motor design so you can typically use a manual a few years off from your actual year model.

 

[nytebyte]

I have a 1982 that runs great with 90 on each cylinder by my tester.

 

[Pappy]

You will get many different numbers on compression in here and that is normal. The main thing here is that both cylinders should be within 10% of each other and compression should be over 80 at least in that engine. Compression gauges are all different and cranking speeds are all different from person to person or battery to battery. Lots of variables, hence the difference in numbers.

 

[ocbinva]

I appreciate all the great information. I usually buy a vehicle to refurbish annually. This year think I'm going to stick to an outboard. I have zero dollars into it. Wost case it becomes a parts engine. One last question. Should I put a squirt of MMO and let it sit for a day or two before I try to turn it over. That is something I've had great success with on Vintage tractors and old Briggs engines but OBs have much higher tolerances.

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[heron2000]

Try looking at "Leeroy's Ramblings" web site - lots of good info

 

[Pappy]

I appreciate all the great information. I usually buy a vehicle to refurbish annually. This year think I'm going to stick to an outboard. I have zero dollars into it. Wost case it becomes a parts engine. One last question. Should I put a squirt of MMO and let it sit for a day or two before I try to turn it over. That is something I've had great success with on Vintage tractors and old Briggs engines but OBs have much higher tolerances.

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It won't hurt a thing. These engines are not like automotive though. They have needle and roller bearings supporting the crank and rods. You can give each cylinder a squirt or two of simple outboard oil in place of MMO as well. Doing this will usually only lube the cylinders and rings and not get into the bearings. I have brought many many of these particular engines back into service. They are much simpler than you may be thinking. The chance of it only being a parts engine is close to zero from sitting that long.

 

[ocbinva]

Well I will post my progress. I travel allot for work so it will take some time. I will start with the basics and if that don't work I might tear it down. I have rebuilt everything from Cares and trucks to tractors and lawnmowers so I am intrigued with rebuilding an outboard.