1986 Mercruiser 260 Advice

[LakeMichiganBoater]

Just got a new to me 1986 Carver Santa Cruz (27') with a Mercruiser 260 (gm 350) and pre-alpha outrive. I am rebuilding the outdrive and have already rebuilt the carb. Engine runs great, but I need some advice on a few things.

1. Where do you drain the oil? Where is the oil dip stick? What oil and how much is used?

2. What fluid and how much is used to refil the outdrive? (I've rebuilt cobra outdrives before, first alpha)

3. Anything special I need to know about changing the distributor cap and rotor?

4. How hard is it to change plugs on this engine?

Thanks!

 

[Scott Danforth]

you suck the oil up thru the dipstick

dipstick should be port side on the motor

you fill it until it hits the full mark

quicksilver high performance gear lube is the general use gear lube

the rotor is usually glued on

changing plugs depends on access to the motor. some bilges you hang upside down. others you lay a pillow over the motor and lay on top the motor

 

[crazy charlie]

Just got a new to me 1986 Carver Santa Cruz (27') with a Mercruiser 260 (gm 350) and pre-alpha outrive. I am rebuilding the outdrive and have already rebuilt the carb. Engine runs great, but I need some advice on a few things.

1. Where do you drain the oil? Where is the oil dip stick? What oil and how much is used?

2. What fluid and how much is used to refil the outdrive? (I've rebuilt cobra outdrives before, first alpha)

3. Anything special I need to know about changing the distributor cap and rotor?

4. How hard is it to change plugs on this engine?

Thanks!

I would recommend that before you rebuild a pre alpha drive, you should consider replacing it with an Alpha one drive which is a direct replacement and a much better drive unit.An Alpha drive takes just over a quart of gear lube 90 weight marine.Filled thru the lower drain plug on the drive until it starts coming out of the upper plug.It would be money and labor better spent.A pre-alpha drive basically has no value to add to the boat.Motor must be properly warmed up to thin the oil to drain thru dipstick.It will require a vacuum device which will cost 50-$100+ unless you get a hand pump which using it will be equivalent to a good workout at the gym and messy. A single engine boat might give you access to the drain plug in the oil pan.If accessible and not rusted ,I would recommend draining thru there and replacing with a fitting and hose which will make future oil changes a breeze.BTW good luck getting to the oil filter.I drain my oil and wait till the motor cools to change the oil filter, you will see why when you do the change.SAE 30 is called for and 15w40 is also good ,avoid synthetics.
Single engine boats have easier access to plugs but there always seems to be something in the way when you have manifolds covering that area. Good luck!! Post back progress.Charlie

 

[LakeMichiganBoater]

you suck the oil up thru the dipstick

dipstick should be port side on the motor

you fill it until it hits the full mark

quicksilver high performance gear lube is the general use gear lube

the rotor is usually glued on

changing plugs depends on access to the motor. some bilges you hang upside down. others you lay a pillow over the motor and lay on top the motor

What motor oil is recommended for this engine? Any idea on the oil filter part number?

What glue should be used to reattached the new distributor cap?

 

[Scott Danforth]

I would run Rotella 15w40 diesel on your flat tappet motor

Gluing the rotor is not needed. Some dork at Mercruiser thought it was needed

 

[LakeMichiganBoater]

I would recommend that before you rebuild a pre alpha drive, you should consider replacing it with an Alpha one drive which is a direct replacement and a much better drive unit.An Alpha drive takes just over a quart of gear lube 90 weight marine.Filled thru the lower drain plug on the drive until it starts coming out of the upper plug.It would be money and labor better spent.A pre-alpha drive basically has no value to add to the boat.Motor must be properly warmed up to thin the oil to drain thru dipstick.It will require a vacuum device which will cost 50-$100+ unless you get a hand pump which using it will be equivalent to a good workout at the gym and messy. A single engine boat might give you access to the drain plug in the oil pan.If accessible and not rusted ,I would recommend draining thru there and replacing with a fitting and hose which will make future oil changes a breeze.BTW good luck getting to the oil filter.I drain my oil and wait till the motor cools to change the oil filter, you will see why when you do the change.SAE 30 is called for and 15w40 is also good ,avoid synthetics.
Single engine boats have easier access to plugs but there always seems to be something in the way when you have manifolds covering that area. Good luck!! Post back progress. Charlie

Oh... This is not something I had not thought of, didnt know they were that compatable. That is a really good idea.... spent $500 on parts for the rebuild of the pre-alpha (actually think is an "R"), but I should be able to return them.

Can you just confirm that I am correct with my belief it is a "R" pre-alpha and an alpha gen I would bolt up to the bellhousing/gimble that is on the boat?



Thank you for all of the advice! Going to start getting together the oil/filter and oil drain pump. I may have a drain hose, but I didnt see one.

 

[LakeMichiganBoater]

I would run Rotella 15w40 diesel on your flat tappet motor

Gluing the rotor is not needed. Some dork at Mercruiser thought it was needed

This oil? T4, non-synthetic or synthetic blend? https://amzn.to/3y3aCIc

Thanks!

 

[Scott06]

This oil? T4, non-synthetic or synthetic blend? https://amzn.to/3y3aCIc

Thanks!

Non synthetic rotella for the older flat tappet engines.

your R drive is close enough to an alpha gen one I would not bother to upgrade. The R/MR/Alpha gen one are basically the same drive with minor revisions.
if you had an older MC1 I would do the upgrade. all the mc1 , r, Mr, and alpha gen ones are bolt in interchangeable. I belive you can also swap uppers and lower except maybe the early mc1 with preload pin ( could be wrong on preload pin).

if you really like the boat and wanted to upgrade for the long term , get a ‘91 and up gen two transom housing and outdrive . That would upgrade all to current production parts.

 

[LakeMichiganBoater]

Non synthetic rotella for the older flat tappet engines.

your R drive is close enough to an alpha gen one I would not bother to upgrade. The R/MR/Alpha gen one are basically the same drive with minor revisions.
if you had an older MC1 I would do the upgrade. all the mc1 , r, Mr, and alpha gen ones are bolt in interchangeable. I belive you can also swap uppers and lower except maybe the early mc1 with preload pin ( could be wrong on preload pin).

if you really like the boat and wanted to upgrade for the long term , get a ‘91 and up gen two transom housing and outdrive . That would upgrade all to current production parts.

Oh, So not worth the upgrade? Then I will stick with my plan to rebuild mine. I am having trouble confirming my model of outdrive though. Could anyone confirm that the serial # 0b463371 is for a MR or R?

 

[Scott06]

Oh, So not worth the upgrade? Then I will stick with my plan to rebuild mine. I am having trouble confirming my model of outdrive though. Could anyone confirm that the serial # 0b463371 is for a MR or R?

Shows as a R/MR drive by typing serial in marine engine’s part search

https://www.marineengine.com/parts/mercury_marine_parts/sn/0b463371

 

[LakeMichiganBoater]

Shows as a R/MR drive by typing serial in marine engine’s part search

https://www.marineengine.com/parts/mercury_marine_parts/sn/0b463371

Thank you!

I will continue with my rebuild of the current outdrive.

 

[dubs283]

R = pin on top end of lower driveshaft

MR = no pin on top of lower driveshaft

Has to do with the cut of the gears in the lower gear case assy and how the lower driveshaft bearing is facing/loaded during drive operation

You will need some special tools to rebuild the drive and depending how far you're going into it parts and special tool investment could outweigh the cost of an sei drive

 

[crazy charlie]

Oh... This is not something I had not thought of, didnt know they were that compatable. That is a really good idea.... spent $500 on parts for the rebuild of the pre-alpha (actually think is an "R"), but I should be able to return them.

Can you just confirm that I am correct with my belief it is a "R" pre-alpha and an alpha gen I would bolt up to the bellhousing/gimble that is on the boat?

View attachment 397579View attachment 397580View attachment 397581View attachment 397582

Thank you for all of the advice! Going to start getting together the oil/filter and oil drain pump. I may have a drain hose, but I didnt see one.

Your drive is not a "PreAlpha" as you originally stated so stick with your original plan.The pre alpha drive has a small loop ring on the top plate and smaller upper with ridge lines on the sides of the upper.Easy to tell the difference. as I previously stated re oil ,dont use a synthetic or blend.Older engines were built to use conventional oil.Charlie

 

[Scott Danforth]

no such thing as a "pre-alpha" there is types I, II, III, MC-1, R, and MR

What is a ‘Pre-Alpha’ drive?

What is a ‘Pre-Alpha’ drive? We see this all the time…. I have a ‘pre-Alpha’ drive, can you tell me…..??? What parts do I need for my ‘Pre-Alpha’? And so on…. Before anyone can answer those questions, we need to know, exactly WHICH ‘Pre-Alpha’ drive do you have? Mercury never produced a...

forums.iboats.com

 

[Scott06]

no such thing as a "pre-alpha" there is types I, II, III, MC-1, R, and MR

What is a ‘Pre-Alpha’ drive?

What is a ‘Pre-Alpha’ drive? We see this all the time…. I have a ‘pre-Alpha’ drive, can you tell me…..??? What parts do I need for my ‘Pre-Alpha’? And so on…. Before anyone can answer those questions, we need to know, exactly WHICH ‘Pre-Alpha’ drive do you have? Mercury never produced a...

forums.iboats.com

oh god don't bring this up again.... it makes the oil threads look interesting.

Seriously world would be great if everyone knew their serial number

 

[Scott06]

R = pin on top end of lower driveshaft

MR = no pin on top of lower driveshaft

Has to do with the cut of the gears in the lower gear case assy and how the lower driveshaft bearing is facing/loaded during drive operation

You will need some special tools to rebuild the drive and depending how far you're going into it parts and special tool investment could outweigh the cost of an sei drive

This is good advice, especially depending on the experience of the OP.

I recently bought the tools for the upper used off eBay , seems like several folks like ourselves were selling the OEM tools that they probably used 2-3 times total. In perfect shape for about half the cost of new

 

[Pmt133]

Seriously world would be great if everyone knew their serial number

It's great and would be nice... and then there are the select few people like me with a Frankenstein setup...
Gen II engine
R transom assembly
MC-1 propeller shaft housing
MR/Alpha driveshaft housing...

 

[Scott06]

It's great and would be nice... and then there are the select few people like me with a Frankenstein setup...
Gen II engine
R transom assembly
MC-1 propeller shaft housing
MR/Alpha driveshaft housing...

I also have a frankenstein, although not as many different generations.

Converted a 4.3 Vortec (cracked block) to a 5.0 with Edelbrock 4 bbl, used wiring and all accessories except ignition module off the 4.3 so I don't have a merc engine serial number. Still using the 4.3 drive and transom so that is straight forward

 

[Pmt133]

I also have a frankenstein, although not as many different generations.

Converted a 4.3 Vortec (cracked block) to a 5.0 with Edelbrock 4 bbl, used wiring and all accessories except ignition module off the 4.3 so I don't have a merc engine serial number. Still using the 4.3 drive and transom so that is straight forward

Yeah it's about as mismatched as you can get I think... dad built the original drive from the 3.0l when he got the boat from bad cores and basically junk he had in the shop at the time... you know, stuff you'd never put on a customer's boat but still good enough to gamble on for yourself since its junk anyway.

Then I found a complete unit when I did the 4.3 swap. The lower unit was badly rotted so I reused my old lower Again. We believe the lower is from his first boat actually... That lower has been together since 1997 so it's had a good service life for "junk" lol.

I'll stop derailing this thread now.

 

[LakeMichiganBoater]

Haha thank you all. Realized in misspoke with I called it a pre-alpha. Confirmed it is a R/MR and I will be rebuilding it.

Ordered T4 Rotella 15w40 (non synthetic), just looking for the oil filter now. Ordered a oil extraction pump also.