TOPIC: Need info on 1965 Corson i/o

Hello, new member to the forum here. I just recently acquired a 1965 ~18 ft Corson with a straight 4-cylinder Chevy? 120 hp block hooked in to what I believe is a MerCruiser outdrive, but I am not sure. Looking for information on how to positively ID the stern drive unit, as well as where I could get a hold of a manual. Any help is appreciated, thanks in advance.

Welcome aboard Marshall, glad to have you join us. Congrats on your recent purchase, some pics of your new acquisition would help the gang identify your drive train in short order. Besides, we just love pics around here!

PS - If you have any trouble posting pics, there is a thread "thumb tacked" at the top in the support forum, very helpful info there.
www.fiberglassics.com/glassic-forums/7-support/22256-how-to-post-pictures.html

Thanks for the reply Mark. I've got a couple overview shots of the boat I'll post now, and then try to get a few more of the drive train soon, as best I can, considering the boat is shrinkwrapped for the winter. Here goes...

Good looking rig Marshall! Sure looks like a Mercruiser outdrive (and controls) to me, but I'm as far from an expert on I/O's as you can get.

Is that a galvanized Tee Nee trailer under it? Very cool, even if it's just painted, IMHO. Very nice find, I'm sure the gang here can (and will) help you with what ever info you need to get her ship shape.

Affirmative, it is a galvanized Tee-Nee trailer - is that a good thing? My knowledge of trailer pedigree is limited, at best.
I bought the boat/trailer in late August - it hadn't been in the water for about three years, but was stored inside. Exterior hull is in fantastic shape, the inside will require a little glass work here and there - but I have a pretty good amount of experience with glass-work and marine carpentry.
However, I don't know a lot about marine mechanical systems. Shortly after buying her, I hooked up a new battery and put her in at a local lake for trials. The Chevy block definately needs a tune up, but started and ran o.k. The issue seems to be with the transmission. Engagement into forward gear was violent, and the slowest speed I could maintain kicked up a monster wake. Reverse gear was non-existent during the trial, but I did witness it go into reverse before I bought the boat.
I ended up getting her up to ~80% throttle and the boat went well underway, but I really want to get this thing tuned up and running reliably, so I can take the family out in the river with confidence. I'll take your advice Mark, and wait for the i/o experts to chime in here..

marshall wrote:

The issue seems to be with the transmission. Engagement into forward gear was violent, and the slowest speed I could maintain kicked up a monster wake. Reverse gear was non-existent during the trial, but I did witness it go into reverse before I bought the boat.

That is definately a MerCruiser. Back in '65 there was a 110 & 120. Both based on the same block. However, in 1965, the outdrive was white. Was that repainted? Is it newer that you think (1966 or later)? I would like to see close-ups of the drive & engine (yes, I know the boat is shrink wrapped). Best case scenario is that the boat is a 1967. Then the drive is interchangeable with drives still available new in a box if you were inclined to spend lots of $$$.
Can you get a serial number from the drive?

As for your shifting problems:

1) Most likely problem is a bad lower shift cable. However, cables from the control box do get stiff & will aggrivate the problem. You need to verify smooth operation & proper adjustment.

2) If that really is a 1965, then it most likely does NOT have EZ Shift. Regardless of what you do, it will never pull out of gear as easy as a 1966 or later unit with EZ Shift.

3) Hopefully, gears & shift dog are OK cause they are hard to find & expensive. If that is a non EZ Shift model, the lower shift shaft is also hard to find but a good machine shop can make one if yours is corroded.

Jim

Thanks for the response Jim - great feedback, just what I am looking for.

However, in 1965, the outdrive was white. Was that repainted?

Not at all sure on that one, I'll take a closer look and include pictures of the block and outdrive as you requested this weekend, when I am home during daylight hours. I'll also take some shots of the controls and dash instrumentation, and try to locate the outdrive s/n - where specifically should I look? I've tried to locate any identifiable markings on the outdrive with no luck (which leads me to believe that it has been painted, as you suggest)

Assuming the best, that it is a '66-67' with EZ drive controls, and the shifting problem is predominantly a cable issue, can you direct me to any literature that addresses cable replacement and maintenance?

Also, what makes the '65 model so problematic to upgrade? Can't the controls and cables just be replaced with an EZ drive or newer? Thanks,

Marshall

MerCruiser 110 HP used the same basic 153 CID GM block as the 120 and the later 2.5L into the 90s.

There were however several manifolds used from 1962 thru 1966 that consisted of aluminum with 1/4" bolts, aluminum with 5/16 bolts, cast iron with the t-stat in the rear and later cast iron with the t-stat on the front of the head. this last design is the one they used for eternity and parts are still available.

As for engine serial numbers, there should be a tag riveted to the block near and most likely just above the starter.

Outdrive serial numbers were on a decal which is most likely long gone. They were also stamped into the outdrive typically on the side of the upper housing near the oil level screw.

The original MerCruiser outdrive was a #1 drive that swung a 14" dia prop and only was built about 1 year. It was then upgraded to a #1A, B or C (depending on gear ratios best I can tell). About 1965 they came out with a #1A, B or C with EZ Shift. In 1967 the drive was again changed to a #1 with 120-160 nomenclature. Eventually the #1 drive was used with angines up to 260 GM blocks by 1978. All #1 drives from 1967 thru 1982 look similar and will physically interchange and bolt onto the bell housing. However, there are gear ratio differences internally depending on the HP of the application. Also, the drive was updated in 1970 with a better prop shaft & lower bearing carrier. All drives except the 1st model year use a prop up to 16" diameter.

Now taking what I said in red above, There were 3 different gaskets used in the 1960s to bolt up to the bell housing. Thjey are all very similar but different. The location of the centerline of the drive shaft/u-joints varies slightly and as such, the 1962 thru 1966 drives can't just be simply updated with a bolt on later drive. Parts for these early drives are hard to find also.

Alright Jim, I've got what I think is the outdrive s/n, stamped and located port side and below the oil fill screw. B1901968. The second to last digit "6" is pretty mangled, and therefore my best interpretation. I'm guessing the "B" donotes a specific gear ratio, as you state in the previous post.

Pics to follow this weekend. Man, so much to learn!

Hope this helps:

110 HP used from 63-66 s/n 1537370 thru 2044033
120 HP used from 64 thru 72 s/n 1666601 thru 3377340
#1 drive (14" dia) 1963 only s/n 1534570 thru 1684187
#1A, B, C (16" dia) 1964 only s/n 1684188 thru 1777798
#1A, B, C w/EZ Shift 65 & 66 s/n 1776349 thru 2065189
120/160 67 thru 69 s/n 2062141 thru 2791956

I would guess you have an EZ Shift. Look on the engine where the shift cable from the remote control is coupled to the cable that runs down under the engine & out thru the transom. At this adjustment point where they meet, you should find a fork type lever with a switch that rests in the center of the fork. When that switch rocks either way it will operate the switch. This is the EZ Shift mechanism.

Best I have ever been able to determine, the serial numbers ran in sequence with the Mercury outbd products.

Best guess is a 1965 or 1966 boat & drive. The engine & transom plate should be black, drives were white until sometime about 1965/1966 when the transition took place, 1967 was black.

You will see that I don't list 1962 in this reply. That is because Mercury doesn't list 1962. However, the engines were introduced before 1963. The 1st year or so (late 61 & 62), they were trying to get boat builders to buy the product & design/build a hull it could be installed in.

Sure does help, thanks again for the excellent information. I was able to take some photos today. I forgot to take shots of the outdrive, but it looks like we have a positive i.d. on that from the s/n. Once we can confirm the identity of the drive train and its components, I would very much appreciate any leads you could provide with respect to manuals, or other maintenance literature - so that I can start working on getting this rig to operate as smoothly as possible, given the condition and age. Pics below...

The motor is not the original. From what I can see, it is a 120 (yes I can read the placard too). I am basing that on the visible part of the exhaust riser & the fact the carb sits with the bowl forward. A 140 has the carb rotated 90 degrees.

I have circled the area where the serial number would be located on the engine block (riveted on data plate) and the EZ Shift mechanism.

You need to disconnect the shift cables at the transom & determine if either one is binding. My guess is that the one going down to the drive is bad. If it is below freezing out, you can't get a good feel because there will be moisture (ice) in the cable & you may not be able to move it at all.

The manuals are as follows:

operator's (owner's) for the 1964 - 1966 110/120 HP #90-38393
operator's (owner's) for 1967 & later 120 HP #90-14567
service manual all years prior to 1974 #90-68648 (2 volume set)
engine parts 120 HP s/n 3377340 & below #90-37325
outdrive parts #1A, B, C w/EZ Shift #90-38973

All books are still available the Mercury Marine. You may find them on ebay also. I would not buy Clymer or Seloc books. They are poor at best & absolutely no help on the pre 1967 drives.

Ok, back at it now that my crazy work schedule has slackened off a bit and I finished some home improvement projects for the better half. Boat is now moved out of the backyard and into the driveway. Still need to get a positive ID on the engine s/n, that will follow soon.

The first project I am looking to start is upgrading the fuel system. The boat came with an outboard-type metal tank just sitting on the aft sole, port side, under the seat adjacent to the engine compartment - not even held down with straps or brackets or anything. When new, the boat had two tanks located port and starboard on either side of the engine compartment. The aft deck fill fittings are still in place, as are the vent fittings located on either side of the hull, aft.

In the short term I will be replacing the tank on the port side, then later think about adding another at starboard. I purchased a low profile Moeller below-deck 12-gallon tank that fits the compartment nicely. Tank comes with fill, vent, fuel line fittings, and I also bought hold-down brackets. I'm not sure what structure is under the sole that would provide an adequate backing plate for the brackets, so the plan is to glass in marine plywood cleats with bi-axial tape and cloth to mount the tank on. Also have to do a little glass work on the sides of the compartment while I'm in there. Then, apply some left over 2-part epoxy primer and some topcoat paint and install the tank. All hose and fittings to ABYC standards.

My question has to do with installing a primary fuel filter/water separater because of the ethanol in today's fuel. The reading that I have done on sizing a primary filter to the engine says the filter must have adequate flow capacity such that it never restricts flow to the engine, under all operating conditions. Not sure what that flow rate is for my engine, would appreciate any input on that, as well as what filter brand are recommended for a river to costal marine environment. My plan is to glass in a mounting pad to the inside of the transom to mount the filter to.

Also, Jim, regarding your previous response, were you able to confim from the pictures that this boat does have an EZ drive?

Thanks,

Marshall

Hi Marshall, good to see you back at it on the project! I believe the ff/ws is a good idea, but as Jim and I have discussed they can provide a false sense of security if not maintained regularly. Mounting a unit in the engine compartment means you must use the metal bowl version to meet USCG regulations, and that makes it more of a chore to check for water in the bowl. (Manually drain a little fuel for inspection instead of just looking in the bowl.) That being said, they do provide additional filtering and a safety net to remove most of the water from the fuel before it gets to the motor.

I would recommend at least a 30 gph (gallons per hour) unit, even though your motor won't use nearly that much. Here's a link to some good info on some of the units I'm familiar with;
www.parker.com/literature/Racor/7480H_Catalog_Marine_Fuel_Filtration_April_2010.pdf
I run the 15 gph unit on my outboards, but it's easy to get at the unit to check the bowl and change filter, etc.....hth

marshall wrote:

Also, Jim, regarding your previous response, were you able to confim from the pictures that this boat does have an EZ drive?

Thanks,

Marshall

The 1st picture I have circled above showing the transom plate has the EZ shift switch, so yes it is an EZ shift model. Keep in mind that EZ shift ONLY allows for EZier (how do you spell that?) shifting while shifting OUT of gear with the engine running. If your boat shifts hard when shut off, your cables are junk and/or the control box needs to be lubricated.

As for the fuel filter, BRP(OMC) and Mercury marine make complete kits. BRP #174176, Merc #35-802893A4 or 35-802893A4Q4.

Sierra also makes a kit, 18-7852.

All 3 kits will work fine, but the Merc & Sierra elements are more common and interchangeable with each other.

Jim, I have a 1966 Shell Lake Caravelle with a 120HP 2.5L MerCruiser I/O that I have restored. Over this past weekend I took her out for trials at a nearby lake and had some shifting issues and was hoping you could help?

Prior to the lake trials, I hooked the boat up to muffs to make sure the motor and outdrive were properly working. I also went through neutral, forward and reverse positions and everything worked perfectly.

However, after putting the boat into the lake the motor died after engaging to "forward" from neutral. After multiple restarts I was still unable to go from "neutral" to "forward" without the motor dying. The engine never died when shifting from "neutral" to "reverse."

Do you have any ideas/recommendations on what may be my issue?

Thanks,
Jon-Erik

Your shift interruptor switch (EZ shift) is operating for some reason. Those reasons are either the lower cable is faulty or you have too much forward travel adjusted in.

I have seen 2 different scenarios listed below that cause reverse issues when parts are not faulty but the fault could be overlooked during troubleshooting.
1st, where old grease accumulated around the cable threads and dried up like a little dam causing the "shoe" to hit and essentially run out of travel shifting into reverse.
2nd, where the early style "forward entry" shift cable is replaced with later "aft entry" design cable. This involves threading the bell housing hole all the way through. If the threads are cut too shallow, the cable will tighten but not seat deep enough and the "shoe" will hit the hex portion on the cable housing again running out of travel.

Neither of these are your issues but it stands to reason if some type of debris has accumulated in the hollow cavity of your outdrive the cable will run out of travel shifting into forward.

All this being said, I am assuming forward gear and the sliding clutch are OK.