1965 Cobia (w Mercruiser 60) repair question.

[propellanttech]

OK...I have heard all the info about the Renault 60 engine...and the "o" drive, so no need to discuss that. I am keeping this boat original for a few reasons.

First the boat is immaculate. It runs great, and I love to keep anything in this condition as close to original as I can. I'll have the parts made if anything ever happens. I know parts are almost not available.

With that said....I have encountered a problem.....

I just recently purchased this boat...and it really is in great condition, with a few minor problems. The most important one is the rear transom seal. It is not bad, but is going to need replaced.

I have pulled the motor, and the four bolts to the inner transom plate, but can not seem to remove the inner transom plate. I have looked through the exploded views online, and can not see anything that would prevent the inner transom plate from being removed.

The outer drive is removed.....so it can not be the shaft or anything associated with it.

Anyone have any ideas?

I am going to restore this boat to factory condition....(very little work....just some bright work after the transom seal), but will need to get this plate off.

J Long

(just for information......I am going to download the service manual later tonight.....my internet bandwidth is limited.....satellite and all).

 

[danond]

Re: 1965 Cobia (w Mercruiser 60) repair question.

They get stuck after decades of use. Try popping it off with a gentle pry with a prybar. Gentle!!

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Well, because the original owner took such great care of the hull and drive system, I figure the engine and drive have been out before.

We tried the gentle approach, and it didn't work. We suspect the last time the inner transom plate was off.....the owner may have used some kind of sealant.

We are going to use hot air to try and see if we can get the sealant to turn loose. I have a precision hot air gun for PCB work, and I can control the temperature. So we think that will be our next move.

If we can not get the inner plate off, the outer transom plate will be sealed and tackled again this winter.

We are starting to wonder what is actually holding the inner plate on. It is really on there.

J Long

 

[JustJason]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Why do you need to pull the inner plate off? Unless your redoing a transom there is no need to pull it.

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Because if you buy a 43 year old boat and not pull the transom plates you will be sorry.

I am careful about looking at everything, and good thing too. We found a two inch area just below the keyhole that is soft and will be repaired.

The exhaust cover nipple was holding the transom plate in place. We did break it, so a search is on for one. We will also need the gimbal transom housing. There has been some galvanic erosion so we are going to replace these parts.

This boat is going to be a nice classic when we get finished. Now on to the part search.

J Long

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Well......just an update for anyone who is interested......

We had to order a transom gimbal bell housing.....and it should be here Wednesday of next week.

We also ordered and received the exhaust cover and a few gaskets that were needed when we took the transom plates off the boat. I figured a lot of these would have to be hand fabricated, but I have been lucky so far finding every piece we need.

We are going to replace all the transom bolts with the best stainless steel bolts we can find.

There are a few things we are going to source locally. The gasket material for the exhaust cover (inner transom plate) will be found locally.....but is not a problem.

I am planning to replace the gimbal housing at some point, but we are going to wait until next year for that. I have found one.....so no problem on the part. I may order it soon just to have it on hand for the replacement next year.

We are having a problem getting the pivot pins out of the gimbal ring. But if needed we will drill and ease them out, and construct new ones from stainless. We have access to a full machine shop, so most small items like that can be constructed.

Next weekend we should start the re-assembly of the drive. Should have it back on the water for a test run in two weeks.

We are going to try fully synthetic Mobil 1 Extended performance oil in the Renault engine, but this will wait until next year. We are also going with fully synthetic lower unit oil, probably Sierra.

Doubt we get much ride time this year, as the water and weather seems to be getting pretty cold, quite quick.

Just as a side note....all of the parts so far have been New Old Stock. We haven't had to go with any used parts up to this point.

J Long

 

[zbnutcase]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Just ran into that problem yesterday(9-18-09), ended up unbolting engine from bellhousing, not too hard really and steering tube came right out. Where are you ordering parts from? 'nutcase

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

I'm ordering parts from just about every dealer across the US.

You have to search around for a dealer that has the part you need. So far I have not ordered a used part. I thought I may need to....I needed a bottom gimbal swivel pin and found out there were only three left in the US. I bought one of those NOS parts.

If you email me off list (EDIT: email address removed, not allowed on the forums. Please use the private message function for personal communications) I'll get you in touch with some of the dealers which have had the parts I needed.

I have all the parts needed coming to me as I type. Next weekend I should have the drive totally back together.

James L

 

[rodbolt]

Re: 1965 Cobia (w Mercruiser 60) repair question.

and in the end you will find, like I did why merc quit using that setup.
its absolutly gutless.
works well, just gutless.
I actually owned one in the early 80's on a 17 thunderbird.
was a nice rig just no power.
keep us updated, not many folks ever actually saw that drive and fewer ever worked on it.
dont lose the tilt crank lever, we did and it was not avalible then.
I also drove a 57 renault dauphine when young too

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

and in the end you will find, like I did why merc quit using that setup.
its absolutly gutless.
works well, just gutless.
I actually owned one in the early 80's on a 17 thunderbird.
was a nice rig just no power.
keep us updated, not many folks ever actually saw that drive and fewer ever worked on it.
dont lose the tilt crank lever, we did and it was not avalible then.
I also drove a 57 renault dauphine when young too

I have heard the Mercruiser 60 had very little grunt. I haven't run the setup yet, so I have no idea how "gutless" the package is. I did run a 50 HP Fabuglass outboard boat for many years, and it was pretty gutless as well.

We have the tilt crank attached to a float, which is stored under one of the boat seats.

I figure with the price of gas, and the fuel mileage the Merc 60 will provide, I can deal with a wimpy setup. Mostly the boat will pull kids in tubes, and just cruise the lake/river (we have both here).

I'm not one for a power house boat. I would love to have a boat that would drag a 250 lb adult up on a single ski, but I do not want to feed the beast.

My back is toast, so I'll never ski again. I may kneeboard, or maybe get an "Airchair", but neither of those require a large amount of grunt.

I'll get some pictures when I'm done....and let some of the forum people see what the package looks like. (Boat too)

I just bought all stainless bolts to put the drive back on the transom. That should keep them from rusting like the old ones did.

 

[Don S]

Re: 1965 Cobia (w Mercruiser 60) repair question.

You might want to go with galvanized bolts on the transom. Stainless and aluminum do not play well together. Besides, those old rusty bolts have lasted for over 40 years.

 

[rodbolt]

Re: 1965 Cobia (w Mercruiser 60) repair question.

you will never ever pull a 250 pounder up on a slalom with that rig. aint gonna happen.
trust me I owned one.
was a nice package for 2 150 people and 1/2 tank of gas and it would plane kind of.
never would pull a skier.
try the same 60 - 80 HP package with the same hull design using a 2 stroke outboard and figgure a 30-40% power loss with your renualt package.
bad as I hate OMC stringer drives the 1978 johnson 19 ft ebbtide with a twin 1 bbl carb 120 HP electric shift stringer drive was 5 times the boat the thunderbird with the renualt motor ever hoped to be.
other than I share your love of bringing dead things back to life, drop that project .

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

you will never ever pull a 250 pounder up on a slalom with that rig. aint gonna happen.
trust me I owned one.
was a nice package for 2 150 people and 1/2 tank of gas and it would plane kind of.
never would pull a skier.
try the same 60 - 80 HP package with the same hull design using a 2 stroke outboard and figgure a 30-40% power loss with your renualt package.
bad as I hate OMC stringer drives the 1978 johnson 19 ft ebbtide with a twin 1 bbl carb 120 HP electric shift stringer drive was 5 times the boat the thunderbird with the renualt motor ever hoped to be.
other than I share your love of bringing dead things back to life, drop that project .

I didn't say the rig would pull up a 250 lb person. I said I would love to have a rig that would....but do not want to feed it.

The "kind of" on the plane is a interesting statement. What size boat, type, weight?

I'm not going to drop the project. When I get it finished, if I find it doesn't have enough power for me, I'll sell the boat.

I would love to know what your RPM was, and the prop size.

No OMC drives here.

James L

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

You might want to go with galvanized bolts on the transom. Stainless and aluminum do not play well together. Besides, those old rusty bolts have lasted for over 40 years.

Those rusty bolts didn't last that long.....two of the bell housing bolts were rusted into long ago....not much holding it on.

No galvanized. I'm going with Tef-gel to prevent dissimilar corrosion.

James L

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Project update.

Well it has been a while since I posted my progress on the '65 Cobia.

We probably would have hit the water last year, but ran into some interesting problems (and a whole lot of bad words that came out of my mouth). I had to take a break, before I had a stroke.

After cracking the exhaust cover on the interior transom plate, the progress went backwards from there. We found the previous owner (or his mechanic), loved red loctite. Every bolt, nut, screw on the drive has red loctite on it. Needless to say, there were quite a few things destroyed trying to get them apart. The pins that let the unit tilt upward were in so tight, they took the threads out when removed (one gimbal housing scrapped). The gimbal ring was also destroyed when taking it apart.

Who ever did this was a fanatic. A bolt, which could never come loose, that kept the upper gimbal ring pin in, even had loctite. I was furious. What an idiot.

I swear, if I ever see anyone put red loctite on a Mercruiser drive part, I will beat them with a lug wrench. The only thing red loctite is good for: spending money replacing parts. Use blue or purple. Never red nor green.

So here is a list of items that have been purchased so far:

Exterior Transom Plate (corrosion, which started this ordeal)
Interior Transom Exhaust cover (it's nipple was corroded in the exterior plate)
Gimbal Housing (suffered from loctite madness)
Gimbal ring (another casualty of loctite)
motor mounts (one was broke when we purchased the boat)
All the associated gaskets, and seals (self explanatory)
New water pump impeller and associated parts (for good measure)
Gimbal hinge pins (destroyed them getting out....loctite)
New bottom hinge pin (this pin is for the steering, and the old one was severely bent)

Basically every housing from the transom to the upper drive is brand new.

I haven't yet put the boat back together. I'm going to start again probably this weekend.

Just for you people out there, every part so far is new. They are all NLA parts (NOS). Some I got good deals on, a few I had to pay more than the listed retail price.

I could have fixed most of the problems with some machining, and some ingenuity, but I felt the problems were adding up to a point, that reliability would suffer. There were too many issues to continue with the damaged parts.

I may end up with a gutless boat, but it will look nice.

James L

 

[Fishermark]

Re: 1965 Cobia (w Mercruiser 60) repair question.

I may end up with a gutless boat, but it will look nice.

I know from personal experience that restoring anything old will test the patience of anyone. That's my daily driver in my avatar - a 56 Chevy that I have had since High School - back in 1976. When people tell me - "They don't make them like they used to!" I always respond - "It's a good thing they don't!"

Old cars, and old boats, can be fun to work on and restore, but you need to know what you are getting into. It often doesn't make financial, nor performance, sense to restore to the original... But, you will have a unique boat when you're done that can be a great conversation starter. Keep at it - I trust you will enjoy the result in the end.

 

[HT32BSX115]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Howdy,

I had a 66 Marktwain (150hp I6, Mercruiser #1) that dad bought new. I was 13 when we picked it up.....I sold it in 2005...told the guy I'd buy it back when he was done with it!!!!!

We also had the factory service manual (I had the receipt for it something like $13 plus postage!! )


I remember seeing the Mercruiser "60" in there along with the "other" strange looking drives and being glad that dad didn't buy a boat with #2 drive etc!!


Post a picture of your boat and drive! We all like pictures!!



Cheers,


Rick

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Howdy,

I had a 66 Marktwain (150hp I6, Mercruiser #1) that dad bought new. I was 13 when we picked it up.....I sold it in 2005...told the guy I'd buy it back when he was done with it!!!!!

We also had the factory service manual (I had the receipt for it something like $13 plus postage!! )


I remember seeing the Mercruiser "60" in there along with the "other" strange looking drives and being glad that dad didn't buy a boat with #2 drive etc!!


Post a picture of your boat and drive! We all like pictures!!



Cheers,


Rick

Well, I would be posting pictures already, but my nice digital camera died last year, and I've been spending the camera money on the boat.

I will definitely get some pictures when I'm done. I may get some before if our process continues like it did.

I want to have some picture record of the drive, where people can reference what the drive looks like. Then if they find one, they can weigh the decision heavily on buying it. The parts are not easy to get, some are not available.

James L

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Well, after a long winter I am back to work on the Cobia.

I have the boat back together. I have had some issues, but most of those were results of strange happenings. I purchased some premium fuel, and ended up with rusty water in my fuel tank. The water was straight from the fuel pump. I will not make that mistake again (will buy a water separating funnel).

I am having a small water impeller problem, but I am chalking it up to gaskets not sealing. I sealed the gaskets well, and replaced the cover. That will have to be tested tomorrow.

I went through the carbs to find out, one wasn't receiving any fuel at all. It's inlet screen was totally clogged. They are back on and tuned for idle.

It has been a very interesting endeavor. The most interesting was the bleeding of the hydraulic shift unit. Because of the repairs needed, I had to separate the master from the slave unit. It was a very educational experience. It doesn't bleed like any other system I have ever worked on (nothing like brakes or anything similar).

I'll keep everyone posted of the latest progress.

James L

 

[propellanttech]

Re: 1965 Cobia (w Mercruiser 60) repair question.

Well the 1965 Cobia is back running.

The boat is not as gutless as I had expected. The unit is running a 10.25 x 12 prop, and seems to be perfect. The WOT is about 4800 rpm which is within the specs of the motor.

The boat is a little slow to plane, but runs real similar to our family 1967 Fabuglas boat. The top speed is not very high, about 27 MPH but I do not want a speed demon any how. Speed burns fuel.

I'm hoping to get some pictures of the boat.

If anyone needs any help with an O drive or a Renault/Mercruiser, let me know. I have learned a bunch since starting the project.

James L