Cd-12

bbstacker1 · Jan 6, 2012

While redoing the lower unit on my CD-12, I noticed the water tube seems to have a built in flow restricter in it. I have not noticed or seen this in any of the other motors I have worked on. It is in the lower end about an inch up from where the tube fits into the impeller housing. I know the lower end has been worked on before and I was wondering if someone might have changed the tube and put something on the engine that should not be there or if this is proper to be on this engine?? 1955, 5.5 hp, CD-12

F_R · Jan 6, 2012

Re: Cd-12

That restrictor was used in a bunch of motors. Can't say for certain about that specific one. I used to drill them out, but water here in Florida is just a mite warmer than up there in Maine, so you might want to leave it as is.

bbstacker1 · Jan 6, 2012

Re: Cd-12

Thanx for the quick reply, I am going to be putting it back together later today (after the brown truck gets here) and I would have hated to have to pull it back apart. I did notice that it seemed to be pumping plenty of water even with the old impeller but I wanted to make sure. You are right about the water temp, people are getting going on the ice fishing thing and it was -6 at my house this morning.

samo_ott · Jan 6, 2012

Re: Cd-12

F_R said:
That restrictor was used in a bunch of motors. Can't say for certain about that specific one. I used to drill them out, but water here in Florida is just a mite warmer than up there in Maine, so you might want to leave it as is.

FR, I have never seen or heard of a restrictor there. What was the purpose?

F_R · Jan 6, 2012

Re: Cd-12

A lot of 5.5 and 7.5hp motors had them. I suppose they figured it would run too cold without it. Our cruddy water would plug them up, so I drilled them out. Didn't seem to have any ill effects.

samo_ott · Jan 6, 2012

Re: Cd-12

Huh. Well you learn something every day. Although I tend to shy away form the smaller engines as they don't push me and my 14'er too well!

HighTrim · Jan 6, 2012

Re: Cd-12

I wonder if it also has to do with pressure? Decreasing the volume increases the pressure. Dont know for sure, just thinking out loud.

bbstacker1 · Jan 7, 2012

Re: Cd-12

I certainly could see where dirty (sand, mud, etc.) water could be a problem and cause an obstruction, that restricter is pretty small, I am looking at a 7/64th allen wrench and the hole is about that size, round of course. At any case, I got it all back together, run it in a barrel and she seems to pump plenty of water. Now all I have to do is wait another five months (ice out) and I'll be able to try it on a boat.

1946Zephyr · Jan 7, 2012

Re: Cd-12

Oddly enough, I've owned several of those 5.5's and currently, I own three of them as well as a Fleetwin and I am yet to see a flow restrictor. What's even odder yet is, I, as will as HighTrim and samo_ott live in areas, where they should be more common, being a colder part. Now, F_R is a Florida resident and there certainly wouldn't be a need or desire for a water flow restrictor. Was this an experiment with the small full shift models that I'm not aware about? I'm interested in knowing the scoop on this feature. My guess it is a feature that was experimented with, before the motors ('58 and later) were built with thermostats.

TN-25 · Jan 7, 2012

Re: Cd-12

This is interesting to me as well. I have a Canadian-built AD-12 that I will eventually get to. If this thread isn't too old when I get at it I will post my findings regarding the presence of a restrictor. Who knows, it is a 54 year old motor that could have seen a lot of service over the years. I doubt the motor-ignorant guy I bought it from did any service to it though. He had a lit cigarette while fuel was pouring out of the leaky fuel coupler from the pressure tank

1946Zephyr · Jan 7, 2012

Re: Cd-12

LOL Good to see the two of you lived to tell about it.

At least YOU did. LOL What a Visual I just had

Hey, TN-25, do you by chance have any parts for these old classics? I need something for my HD-20

F_R · Jan 8, 2012

Re: Cd-12

Sorry I don't have any more details about the restrictor. I can't believe it was a regional or experimental thing. Possibly (??) it was used in conjunction with different size drilled holes in the powerhead?? I dunno. But it makes sense that a 5.5hp needs less cooling than an 18hp, yet they use the same size water pump, the 18 just has a bigger drive shaft.

TN-25 · Jan 8, 2012

Re: Cd-12

1946Zephyr said:
...Hey, TN-25, do you by chance have any parts for these old classics? I need something for my HD-20

Zephyr, I don't have much in the way of spare parts hanging around. I don't have anything at all for an HD-20 but I have seen a good number of HD-20s for parts on e-Bay. Probably the casual restorer that finds out just how obsolete the parts are for one (the last ones were made in 1951). I'm looking into joining the Maple Leaf chapter of AOMCI. They will have a local meet near me January 28th. Maybe I can get a lead on some parts sources.

F_R, that is an interesting theory on the use of restrictors. You may be onto something there.

1946Zephyr · Jan 8, 2012

Re: Cd-12

Yea, fortunately, Sea-Way has come through for me on everything I needed so far, Now, all I need for mine is the fuel coupler with the fuel filter, that goes in the tank. I'll probably hit them up for it.

As for the water flow restrictor, I'll have to check it out. I have a CD-11, CD-12, '58 Fisherman and a '54 Fleetwin which is the same as the CD-12, from the powerhead base gasket, on down. Prior to these, I've done many a waterpump job on these, but haven't seen one. One form of restriction that I have seen on these little guys, is where the water tube goes into the midsection. Sometimes corrosion can close that passage off and greatly slow the water flow through there. So, if you find water flow issues, below the powerhead base gasket, that's the first place I would look.

I didn't realize they had the same size waterpump as the 18's. hmmmm learn something new every day

bbstacker1 · Jan 8, 2012

Re: Cd-12

I never really thought about it at the time, but if I ever go back into the foot of the CD-12 I will take a picture of the water tube. I have an AD-11 and I know it doesn't have the restrictor and I just picked up an AD-10, that was mentioned in a separate thread, so I will soon get to check it out. I wonder if it might have been something they tried and then either continued or stopped depending on how it worked out, the ser# on my 12 is 1305540??

HighTrim · Jan 8, 2012

Re: Cd-12

TN-25 said:
I'm looking into joining the Maple Leaf chapter of AOMCI. They will have a local meet near me January 28th. Maybe I can get a lead on some parts sources.

You should definately come to the hard water meet on the 28th. Let me know if you want to come and I can help you out with directions. Great bunch of guys, some real knowledge there. Plus the prices on motors at the meet are great, just dont try to buy any of the ones I want!

wbeaton · Jan 8, 2012

Re: Cd-12

I've never seen the restrictor either and I've owned and worked on dozens of 5.5 - 7.5 hp's. Of course, I've also only worked on Peterborough built motors. Perhaps that has something to do with it. Maybe we didn't get it north of the border.

TN-25. Come out to the Hardwater Meet in Ajax. You don't even have to be a member. I'll be there. I expect samo_ott and Hightrim will be, as well.

samo_ott · Jan 8, 2012

Re: Cd-12

Yes! I'll be in Ajax on the 28th also. Cleared it with the wife a couple of months ago!

It's only a 4 hour drive fro me! C'mon out!

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