Merc Mark 7...The Rocket Lives!

[tmcalavy]

Put the Merc Mark 7 I have been working on in the water tub this evening for a test run. Had to replace coils/plug wires/gas tank and recoil, plus a thorough carb cleaning and improvised fuel line. It fired up and ran on the 3rd pull...yahoo! Runs quiet and smooth, but as I feared the water pump/impeller must be toast...no spray out of the relief holes on the upper back leg. The prop is stuck on the shaft so I'm trolling for advice on how to pull it, before I get out the grinder/cutting wheel and take it off in pieces. I have a good replacment prop, just hate to cut a good one to pieces if I can avoid it. Will heat help? I have a butane/propane bottle torch. If I try heat, what's the best method...heating the prop or the shaft or both? Any input is welcome.

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

Okay, drilled some holes in the old prop today...down the sides between the blades and then connected the dots with a 4" grinder with cut-off wheel. Also removed one blade. Got the prop off without damaging the gear case or the prop shaft. Now I have to make or find a Merc tool to remove the water pump cover. I know it's a left hand thread. Any ideas on making/finding that tool?

 

[Laddies]

Re: Merc Mark 7...The Rocket Lives!

The original tool was a round head with a hole the size of the prop shaft the head had 2 small pins to engage the holes in the w/pump cover or nut, there were 2, 1/2" by about 7" long handles that you could hit with a hammer to knock the nut loose, before we came up with the real tool we used a spanner for hyd. cyl. nuts that I thing was for power trim cyls.

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

Thanks for the info. On another board a member advised that someone had made their own tool using a large, adjustable wrench with holes drilled and filled with pressed-in stainless steel pins. I'm in no hurry, the main worry was getting the prop off without buggering the case or prop shaft. The tool will surface or more good ideas to fab one up.

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

Bump

 

[corm]

Re: Merc Mark 7...The Rocket Lives!

Hi,
You could always try one of these.
Adjustable spanner wrench.

Here is an example. You can get them lots of places.
http://www.sjdiscounttools.com/arm34-154.html

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

So this tool will definitely fit/work to remove the Mark 7 water pump cover behind the prop?

 

[corm]

Re: Merc Mark 7...The Rocket Lives!

Hi,
No it will not. It is for an example only. You will need to measure the holes in the pump cover and then find a Adj Pin Spanner wrench "like" that one with the correct size studs for your cover. Then you may have to heat and bend the wrench to fit in to the cover if it is recessed.

Here is another style:
http://www.armstrongtools.com/catalog/products.jsp?groupID=865

The Merc tool looks a lot like this one.
http://www.duckworksmagazine.com/04/s/columns/max/17/Mercury11.jpg

or third picture up from the bottom.
http://www.duckworksmagazine.com/04/s/columns/max/17/index.cfm

which you can make out of a piece of pipe for a one or two time use wrench.
Providing you can find a piece the same diameter as the holes. Just cut it down to make the pins protrude from the edge of the pipe 180 deg apart.

here ia a "cheap one" http://cgi.ebay.com/Side-Pin-Spanne...4587614QQihZ005QQcategoryZ20774QQcmdZViewItem

THis link will help you see what the dementions are all about.
http://buy1.snapon.com/catalog/item...8&group_ID=603&store=snapon-store&dir=catalog

Lots of tools will cross over from other industries. You just have to look for the aplications that will transfer to your problem.

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

Hey Corm, thanks for the info. Yeah I read the Max W. article and thought "right on brother"...nice outboards but their design sometimes leaves me scratching my head. I tried the adjustable side pin spanner. No go. No way to keep the head/pins down while you are applying torque to the handle...the pins simply slip out. That cover/nut must have been installed by a gorilla with a headache. I have another option to try, using a large adjustable wrench, a drill press, and stainless steel pins. If that doesn't work, guess I'll hold out for the official tool. Can't quite picture how to make one of these out of a piece of pipe.

 

[corm]

Re: Merc Mark 7...The Rocket Lives!

Hi,
Ya they use to tighten them up and then pound them tighter with a hammer.Not the smartest thing to do. If you have a fax machine PM or email me your number and I will fax you a drawing. If I had a scanner I could email you one, but at this time I don't. Spending my $$ on some boats this month.
If you have a heat gun used for stripping paint you could try some heat on it.
They are safe to use as you can not get it to hot. I like a propane torch but do not like to recomend that people use one unless they have already used one to wreck some AL metal. Knowing how hot to get it is important.

You can hold the wrench in place with a tube slipped over the propshaft held in place by a plate and the propnut too. If the tool is to flat so it is hitting the LU edge maybe you can heat and bend an angle in to it.
I have made them out of flat steel and drill bits before like you are thinking about too.

 

[tmcalavy]

Re: Merc Mark 7...The Rocket Lives!

Thanks again Corm. I just PM'ed my fax number to you. I'll proceed slowly and perhaps get the job done this weekend.