66 MQ12A Over heat?

[Bruce San]

My brother dropped off a motor for me to "look at" for him. I think we all know what that means. Any way he bought it from a guy who bought it from a guy who said it runs fine. Upon initial inspection I found lot's of wasp and mud dauber nests under hood. The head is discolored and missing most of it's paint. The bendix is stripped. My compression tester is MIA so I turned the flywheel by hand at first with the plugs in and got compression like resistance. Pulled the plugs and spun the flywheel with a rope and got good blue spark. Dropped the LU and found impeller to be intact. ( will replace anyhow) Don't know about carb yet.

Judging by the outward condition of the head I'm guessing I need to pull it and do a visual inspection of the cyls. The thing overheated at some point for some reason and I don't think it was the pump impeller. How many water jackets can I get at without a complete disassembly?

 

[Bruce San]

Re: 66 MQ12A Over heat?

One more thing: where can I get gaskets and stuff for this?

 

[ezeke]

Re: 66 MQ12A Over heat?

You can get most service parts from a dealer in your area:
http://dealerlocator.evinrude.com/EN/?Rnd=1166189944796
Just select service and enter your zip.

A lot of the 9.5 motors got overheated when people ran them in buckets with weak impellers. I would run the compression check first before tearing into it. Around 90 PSI would be real good, with no more than say 10% difference between cylinders. The water intake screen is just above the propeller, so when you are on the water in forward gear, the propeller forces water into the intake and the cooling system works better.

The thermostat is easy to get to if the cap is not frozen and you can get a pretty good idea of the condition of the cooling circuit ftom there.

You can see the parts diagrams here: just use the 1968 diagram for either Johnson or Evinrude because they are the same except for cosmetic items.

http://epc.brp.com/default.aspx?brands=ej&lang=E

 

[Bruce San]

Re: 66 MQ12A Over heat?

Thanks ezeke! I'll do the compression check and post back.

 

[ezeke]

Re: 66 MQ12A Over heat?

There is a starter pinion on Ebay.com that will fit. Search for 384597.

 

[Bruce San]

Re: 66 MQ12A Over heat?

Well I found my compression tester, at my neighbor's house, right next to my chainsaw.

Top cyl 88, bottom 86. Not to bad I guess.

Pulled the LU drain plug and got several ounces of water followed by some really nasty sludge. I figured it was a goner but took it apart anyway. Once cleaned up the gears, clutch dog and everything else looks fine. No rust. very smooth operation on the bench. The only thing that looks messed up is the driveshaft and bushing where the shaft passes through the upper gear housing just under the water pump. It's grouved up pretty good.

 

[ezeke]

Re: 66 MQ12A Over heat?

I've got six 9.5HP motors. I don't have one that will go 88 PSI, and they all run fine. On that basis I think that you will be fine. Just re-torque the cylinder head bolts.

The drive shafts get worn by the seals over time. That should not be too much of a problem. The BRP/OMC seal kits should come with every thing that you need to close the leaks except sealants. If the driveshaft seal will not hold, you might want to keep a search running on Ebay for one, and change the gear lube more frequently.

The O-ring seal on the shift rod is easily relaced while you have the gearcase apart and impossible otherwise. They often leak, so you might want to tackle it.

Be sure and replace the seals on the fill and drain plugs.

The carburetors are touchy; The high speed jet is fixed and lies in the bottom of the float bowl directly behind the drain screw-plug. It picks up all the junk that settles, plus gum from the fuel-oil mix. You can usually clean it up with a aerosol can of Gumout with the red tube.

The first thing that I do with my carbureted engines in the spring is drain the float bowls.

There is a small hole just under the choke bowl on the starboard side of carburetor. That hole leads back to the high speed jet, so spray from that as well and you should clean out the jet.

Over on the Engine FAQ Iboats forum they have a thread on setting the idle [lean-rich] needle.

The 9.5 was made for 10 years with little change. They were extremely popular and many were sold. Because of that there are many still around and used parts are easy to find.

If you like the motor, buy another one for parts.

Go to ebay.com and enter 190062772317 in the search window.

 

[Bruce San]

Re: 66 MQ12A Over heat?

Thanks ezeke. I sure do appreciate your help. I've already removed the drive shaft seal from the housing. Is it hard to find a new one? Or were you talking about the shaft? as for the rest of the lower unit, it has cleaned up nicely. I got what was left of the shift rod seal out. It was bad. Can it be replaced without removing the bushing? It looks like you would need the exact right size drift to drive the bushing out.

I found out why it over heated. I took the thermostat and placed it in hot water. I brought it from around 120 to over 180 F and it never opened.

One of the really cool things about the motor is it came with original owner's and shop manuals with a parts breakdown. I'm making a list of the seals and stuff I'll need to take to the local dealer. Hopefully they'll have most of it.

 

[ezeke]

Re: 66 MQ12A Over heat?

Get the gearcase seal kit; it will have all of the seals and the o-ring. Dealers sell one, or you can get one here at Iboats.
http://www.iboats.com/mall/partfind...row.6/keywords.seal kit/session_id.753577029/

If you get a complete water pump kit, it will have everything else that you need for the gearcase and pump.

Use gear oil on the o-ring, bend it in half and slip it in.

Use two small dowels or somethingt similar to push from th bottom and the top and you can push the new o-ring into place.

 

[Bruce San]

Re: 66 MQ12A Over heat?

OK, I ordered the gearcase seal kit, water pump kit and the thermostat kit.

The wife will be pleased to have me out from under foot over the holiday.

 

[Bruce San]

Re: 66 MQ12A Over heat?

Well, the re-seal went very well. My son and I cleaned all the parts up and put it all back together.

One problem however, I bought both the lower unit and water pump kits but, I think I'm missing a seal. On top of the water pump housing where the drive shaft passes through. The parts breakdown shows a seal here and none of the seals in those two kits are big enough to press into the housing.

I guess what I didn't get was 0309607, seal and 0309583, washer. Although I do have a couple seals left over that apear to be dublicates in both kits.

 

[Bruce San]

Re: 66 MQ12A Over heat?

I should add that when I took it apart there was no seal in the top of the water pump housing. Not that that means anything.

 

[ezeke]

Re: 66 MQ12A Over heat?

The rubber grommet seal #309607 that went on the top is no longer available. The extra shaft seal that you have was to fit inside of that.

Sometimes they stick in the midsection where the driveshaft goes up, so check there.

If you don't have it, You can try to set a larger diameter seal like the prop shaft seal, #313282. That is really not a totally acceptable substitute, because part 309607 also kept the exhaust out.

I found that our local dealer was able to find the rubber part from a network that they use, but because of the scarcity, they are really highly priced.

 

[Bruce San]

Re: 66 MQ12A Over heat?

OK I'll look for it on the midsection. I don't recall seeing anything there though.

I wonder if I could dummy something up? I think I can work out the shaft seal problem as you suggested but sealing out the exhaust gasses will be the challenge. A miniature fernco fitting would be perfect.....

I'm assuming you've been able to re-use all yours or found salvage???

 

[Bruce San]

Re: 66 MQ12A Over heat?

Edit: that emoticon was unintentional.

 

[ezeke]

Re: 66 MQ12A Over heat?

I have no spares, I read that the Seattle firm that Evinrude listed has some, so you might call them.

See:
http://www.evinrude.com/en-US/About.Us/FAQ/Older.Vintage.Products.htm

[Edit] Scroll to bottom for companies.

 

[Bruce San]

Re: 66 MQ12A Over heat?

Thanks I'll give 'em a shout.

 

[Bruce San]

Re: 66 MQ12A Over heat?

Ezeke, I found it! Right where you said it would be. The L/U is back on.

I need to pick up a fuel tank and primer bulb/hose and I'm ready to fire it up and see how it runs. I ran some carb cleaner through the bowl and high speed jet as you suggested. I put a clean white shop rag under the bowl drain before I ran the cleaner through. I didn't get any nasties out of it.

I don't know the condition of the fuel pump and carb. I guess I'll find out tonight. If the fuel pump is bad I can overcome that with the primer bulb. Since there is only 1 carb I figure I can't run 1 cylinder leaner than the other.

Is there any reason I shouldn't try and run it now? Anything to check first?

 

[ezeke]

Re: 66 MQ12A Over heat?

Flywheel torque checked?

Fuel mix is 50:1.

Fuel pump is tightly mounted to the engine with a good gasket and has a clean screen.

If you are buying a tank, get an in-line fuel filter to go with it.

If the fuel pump is bad, set the tank higher than the motor and let gravity do the pumping.

Give the engine a few minutes to burn off old fogging oil or whatever before making any adjustments.

Be sure that the water is as far up the midsection as possible. The exhaust kicks a lot of water and the exhaust relief will throw water outward.

After a few seconds, the water should spit out of the exhaust relief all of the time that the engine is running. If it does not, turn it off.

Don't run the motor up too much with no load on it.

I'm sure that someone else will want to make a few suggestions.

 

[Bruce San]

Re: 66 MQ12A Over heat?

I torqued the flywheel last night. I still need to check the torque on the head.

thanks for your help!