TOPIC: Tips for Removing my Powerhead

I'm getting ready to remove the powerhead on my Scott McCulloch 60hp motor so I can remove the side cover. Last year I broke a bolt removing it to replace the bracket holding the spark plug wires. The result was a little water leak that I patched externally (so of) with silicon. I decided to fix it right but I need to remove the powerhead to get to the 3 bottom bolts of the side cover.

The Scott Service manual says:
(1) Remove the hood, then remove the screws that secure the powerhead to the adapter plate.
(2) Disconnect the Fuel Line, batery and junction box leads from the powerhead.
(3) Lift the powerhead assenmble off the drive shaft.

Its sounds easy. Is there anything I should know before I dive in?

Here's a pic of the bottom of a 40hp powerhead I assume its fairly similar to my 60. 13 bolts?

My Scott is just a small 7 1/2. It has 10 bolts. You have to pull the powerhead just to replace the water pump so if your is like that you may as well do it.

Shacomm,
Removing that side cover is one of the toughest jobs on big HP Scott. You have one broken bolt now. You will probably have many more before the cover is off.
But, before removing the cover you will also have a bit of a challenge removing the power head. Removing the wiring, fuels lines, linkages etc., is fairly straightforward. Removing the 13 socket head screws is a little more difficult. Unlike the side cover bolts they do not normally corrode and break off. It's just that three or four of them are difficult to get to. You need to have ball end hex wrenches to get access, and even then you may need to heat bend one of your wrenches to get the job done. The best tool I have ever found is a ball hex wrench that is about eight inches long and has a very short leg for the ball end. Then you need a long hex ball end driver. Most go-kart shops have them for the carbs on Briggs engines.
I suspend the engine on an overhead hoist so I can get easy access to the screws and when I have all but a couple of easy to get to ones left I lower the motor back on the stand, pull the remaining screws and then lift the power head off.
If you don't a hoist or engine lift you will have to work on the engine stand and it gets in the way, or you can lay the motor down to get the screws out.
Then, when the power head is off very, very, very, carefully try to remove each bolt on the side cover. A few may come out, but it's almost impossible to tell the difference between the bolt coming loose or it starting to break. Try to work the bolt back and forth slowly and use the penetrating fluid of your choice. Penetrating fluid doesn't seem to help much because the screws are corroded to the block all the way down the inch of thread.
So, you'll probably get a few out, and you now have a decision to make. You can break the rest off and pull the cover leaving you with a lot of drilling and easy-out work, or you can cut the heads off with a die grinder and cutting wheel, or some similar method. This leaves you with a bunch of "studs" left and with a vice grips and a with a lot of heat for a very short time period from an oxy-acetylene torch (I use a rose bud tip) applied to the block on both side of the screw hole allows them to be easily turned out. You can see on the attached pic of the 75 HP I am currently working on where I had to heat a couple of bolts to get them out. A hand held propane torch won't put out enough heat, but you can give it a try and you might be lucky.
By the way, the 75 hp has more cover bolts than the 60 hp, which tells me the cover has had leak problems in the past and Scott tried to fix it on the 75 hp!
With the cover off you can now heat the center row as well as the outside rows. That's another reason to cut the bolt heads off. It allows you to remove the cover to heat the center bolts.
If you want to reduce the amount of bolt heads to cut you can remove the side and end bolts with heat and then just cut the center bolt heads. You usually have to heat a little more because you can only get to one side of the bolthole this way.
Once all the bolts are out, I use a 1/4-20 bottoming tap to clean each bolthole. Occasionally you will find the tap may hit bottom and keep right on turning. The threads have been corroded away. Now it's time for Heli-coils. I used a 1/4-20 2D (twice the bolt diameter) 1/2 in. long. NAPA may stock them, but they can order them if they don't. Their part number is BK 7703117.
Also, before you install the cover it's a good idea to screw in a 1 in. long 1/4 -20 bolt with a couple of washers in any hole you that you didn't have to Heli-coil. Torque it to 30 inch pounds (factory recommended torque for these bolts) to make sure the threads will hold during the final installation.
I really don’t like recommending patch jobs, but to do this job “right” is a real b**** IMO! Getting Heli-coils in straight and on center is difficult. The block I am working on now had a botched Heli-coil job and even has a broken off tap in one hole. As you can see I use a vertical mill to get the Heli-coils straight and on center.
Instead, you might try to clean your water leak area down to bare aluminum with a wire wheel and try to seal it with JB Weld. That stuff works amazingly well if it goes on clean metal.
Paint it red to camoflauge it a bit, and cross your fingers.
If that doesn't work, then pull the side cover.

Don

Give that man a Karma point.

Wow. thanks!

The good news is I've already removed and replaced all but two of the bolts. They broke I have the bottom three unscrewed about 1/4" but I cant get them out so the power head has to come off.

I used Time Serts on my starter bolt holes and was planning on using them on the two failures.

Thanks for the tip on the ball-end wrenches I have a set and will take a look at getting a bent one. I guess the good news is when this is done I've done the hard part! Thank you so much for the tips.

2x on the Karma!

Thanks to provide tips to remove Powerhead.

By using wrench and a flywheel puller you can remove fly wheel.

www.theoldglassboats.com/TOGB/outboards/Sears-Outboard.htm

If memory serves; this was posted by Handyandy 5 years ago.

Also I need a short shaft drive shaft, water tube, and shift rod to change my 75 Scott from long shaft to short shaft. If anybody has one to sell/trade I sure would like to know about it.
Mine has an extension section just like the 60`s OMCS.

Shacomm,

It looks like you have everything under control. Removing the two broken bolts is the only difficult part left. The bolts are soft so they can be drilled and pulled with an easy-out, especially if you can heat the block enough to expand the aluminum and break the corrosion bond.
I'm sure the inserts you use will work fine. I use Heli-coils because that was all that was available when I started doing this type of work many years ago and I am used to using them and have all the tooling. It's that old dog, new trick thing.
You probably are already familiar with this company, but if not, they have a lot of vintage parts for Scotts.
I get the side cover gaskets from them.

discount-marine-parts.com/ob_mcculloch.html

Don

Yes I ran the motor before removing the bolts and the heat made it easier. Its funny the two that broke were the two that had wire loom brackets trapped. I wondered if that was a factor? I've already drilled and tapped the one broken bolt but the other is just below the cowling so I'll do that one after I get the power head off.

I still have the motor hanging on the back of the boat but it sounds like I'm going to have to take it off to get to the front power head hex bolts.

I was wondering about gaskets. I'll give Discount Marine a call. thanks!