What yrs will interchange on '79 OMC 9.9 hp?

[Valley Boater]

I recently obtained a 1979 Evinrude 9.9 hp. I may have to replace the powerhead as the pistons seem frozen or very tight (they seem to be loosening up slightly after a day's soaking in solvent. Before I spend too much time and money, can someone please advise what years (or models) of Johnson and Evinrude might be interchangeable, esp. the powerhead? I've located a '72 Johnson 9.5 powerhead in decent condition, any chance it would fit? Also, please advise if I would be wasting time and money trying to find parts such as impeller, water pump housing, rings, pistons etc. for this vintage unit.

Model # 40955B (the "4" may be a "A"). I believe this would make it a '79. I'll try to attach a photo in case an expert can help ID.

Thanks to all in advance from a new member.

 

[jeff_smith_0423]

Re: What yrs will interchange on '79 OMC 9.9 hp?

72 9.5 will not fit for certain. completely different design.

You can view exploded diagrams of the 9.9 on @ shop2.evinrude.com

 

[mikesea]

Re: What yrs will interchange on '79 OMC 9.9 hp?

what jeff said and,I would say all of the 80's thru late 90's.But if you find a specific unit you think you might get,look up the year on the BRP website and compare part numbers,also know that ,though 15 hp's have many interchangable parts,they are not interchangable .If your looking for a bit of a project,rebuild yours,it wont cost much.You could likely get away with a honing of the cylinders and change the rings.Unless you find rust inside the engine ,the rods,bearings crank ,can be reused.Pull the cylinder head off and see what you have,if rust ,you probably want to take the powerhead apart.Water may have gotten to the bearings ,rods and crank leaving pits.They are hard to clean up.Let us know what u have and we can go from there

 

[Valley Boater]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Thanks for the feedback and suggestion. The penetrating type oil that my auto shop suggested is starting to pass through the cylinders (as you can see in the attached photo) so I hope I will be able to free up the pistons this weekend. The previous owner said it was running when he last used it and it has been garage stored for the past few years (since he ran it last).

 

[bktheking]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Just did the job, new rings are $50 CAD, new gasket set is $30 CAD, honed for free, cleaned it up and put it back together, mine starts first pull and I put a carb kit in it too.

Cleaned it throughly with a pressure washer and degreaser. I painted the whole motor, rebuilt the powerhead and replaced the lower unit with an sail shaft for under $300, you can't find em that cheap and pretty new.

Check your cylinders for deep scratches, the block might be bad as well, several powerheads have been for sale on the bay over the past couple weeks, in fact I have a lead on one out of florida. Check bearings and crank surface as well, it may have gotten water in the crankcase, that would be a bad thing.

 

[jay mendoza]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Hi, you should look on eBay, as theyre are always power heads availlable. I got one for just $125.00 it ran great. Your engine is an electronic ignition model, they are from 1977 onwards. Your block remained the same until the late 1980s,

look at this auction: http://cgi.ebay.com/ebaymotors/john...9467806QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

 

[Valley Boater]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Nice job!!! I now have the before photos, I hope I will have the after shots for next Spring!

 

[mikesea]

Re: What yrs will interchange on '79 OMC 9.9 hp?

yep,probably just a stick from lack of use,give it a bit more oil for first use,double oil wont hurt anything except maybe an idle problem from plug fouling ,or an extra 1/2 pt.dont push it too hard for half hr,also,its laid up for a long time,expect dirty carb and definatly change the impeller,the impeller on those engines are prone to failure

 

[bktheking]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Nice job!!! I now have the before photos, I hope I will have the after shots for next Spring!

Thanks for the compliments, and if you notice it's a newer block, the powerhead is an 88 but the body is an 83, I think they eliminated the slow throttle knob by 1988.

 

[Rick.]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Keep soaking the cylinders with oil Who knows it may just work fine and save yourself a whole bunch of work. Take the plugs out until you get it turning easy. Once you get it running, do a compression check and see what you've got. I would also recommend a decarb before you make any final decision. I have the same motor and it is a good one. Here is a fantastic site for all 9.9 owners. Lots and lots of useful information. Best of luck. Rick.
http://www.sschapterpsa.com/ramblings/OMC/OMC info.htm

 

[bktheking]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Agreed Rick. If you need help I've tore 2 of these motor apart down to the lower motor pan and i'm pretty sure Rick has too. These are the motors I know the most about, researched them to death and I have some spare lower unit parts as well, just sent someone on here a drive shaft for nothing for a 9.9 short shaft.

 

[Grant Brown]

Re: What yrs will interchange on '79 OMC 9.9 hp?

I'm the guy who he sent the drive shaft to. Thanks again BK. I'm trying to repay the favor with some goodies off a parts motor (powerhead is seized).
My Grandpa, Uncle and Dad all have had these motors. The first boat I learned to handle had one. They are worth a little effort to keep running. If it were me in your situation, I'd try what mikesea and Rick said; try and get it going without tearing it apart. Chances are it will be fine if you take it easy on it at first.
Grant

 

[Valley Boater]

Re: What yrs will interchange on '79 OMC 9.9 hp?

Thanks for all the info and advice. Two days of soaking has freed up the motor. My next step to get the compression tested (I don't have a tester and want to avoid spending $40 to purchase one). I'm optimistic that I will get it running.

 

[jeff_smith_0423]

Re: What yrs will interchange on '79 OMC 9.9 hp?

You can borrow one from most auto parts stores for just a deposit - but it's a good investment to have one anyway. Might even be able to find one at Harbor Freight