New to inboards and have many ?'s

[Menace2Authority]

Hello, been browsing the forums for a while now and I could really use some advice.
I've just purchased a 1979 18 1/2' Doral with a 165 hp in-line 6 Mercruiser engine. Never before have I owned/maintained an in-board motor.
So if you could humour my ignorance it would be appreciated.

A.) I know the impeller hasn't been changed in minimum 3 years so I understand that it MUST be changed before I really run the boat.
Can I do it myself? If so, any links to the process? I am mechanically inclined and do all my own small engine work/re-builds and some of my Truck repair. Are any specialty tools needed? A full step instruction process would be great if there's a link to one.

B.) I was told that the bottom ends have to be filled from the bottom plug up. If this is true I'm guessing the previous owner did not have the pump to do so. If I'm changing the water pump I'm guessing the oil will be drained out of the outdrive anyway, but is it real terrible to fill it from the top? Or absolutely necessary to fill from the bottom?

C.) What would proper running temperature be for this motor with water surface temp averaging 70-80 degrees F.? I'd like to be able to keep a close eye on my engine temp and I'm not sure what normal operating temp should be.

D.) Anything I should be looking for with this motor? Were they problematic in any particular area?

E.) How do I find out which "outdrive" model I have?

F.) Regular or High Octane fuel?

G.) The motor has 825 hrs on it. Is this considered low or high hours for a Mercruiser?

Here's a pic of the motor if it helps at all.

Thanks a bunch! This site is GREAT but I have a hell of time successfully searching for anything on these forum types.

Rob

 

[hamishmcduff]

Re: New to inboards and have many ?'s

I have the l6 165hp aswell and I love it.
I can help you on a couple of things for now but I am no expert as I've only owned the boat for 3 years.

A. yes I would change it, the procedure is not all that difficult and it will be better safe than sorry for this replacement.

B.It is neccessary to fill the leg from the bottom hole.

C.I regularily see 180*F and thats the way I like it

D.Nothing I've noticed.

E.http://www.mercstuff.com/drive_id.htm

F. I believe it is a low 8:1 compression motor I run 87 octane with no issues.

Picture is nice it looks very clean.

 

[45Auto]

Re: New to inboards and have many ?'s

A.) I know the impeller hasn't been changed in minimum 3 years so I understand that it MUST be changed before I really run the boat.
Can I do it myself? If so, any links to the process? I am mechanically inclined and do all my own small engine work/re-builds and some of my Truck repair. Are any specialty tools needed? A full step instruction process would be great if there's a link to one.

Go here and download factory manual #4 for your drive and #3 for your engine. There's a step by step process in #4. You'll need an alignment bar, about $40 shipped off Ebay.

http://forums.iboats.com/showthread.php?p=1693398#post 1693398

If you don't know when the last time the bellows were changed, change them also. They should be changed about every 5 years.

B.) I was told that the bottom ends have to be filled from the bottom plug up. If this is true I'm guessing the previous owner did not have the pump to do so. If I'm changing the water pump I'm guessing the oil will be drained out of the outdrive anyway, but is it real terrible to fill it from the top? Or absolutely necessary to fill from the bottom?

It is ABSOLUTELY necessary to fill from the bottom. There's only a very small oil passage between the upper and the lower. Fill it from the top and you trap a HUGE air bubble in the lower. It will then die very quickly from lack of lubrication.

C.) What would proper running temperature be for this motor with water surface temp averaging 70-80 degrees F.? I'd like to be able to keep a close eye on my engine temp and I'm not sure what normal operating temp should be.

Probably 160-180 degrees. It'll tell you in manual #3 above.

D.) Anything I should be looking for with this motor? Were they problematic in any particular area?

It's a straight 6 Chevy, probably one of the most reliable engines ever made.

E.) How do I find out which "outdrive" model I have?

See manual #4 above.

F.) Regular or High Octane fuel?

Regular

G.) The motor has 825 hrs on it. Is this considered low or high hours for a Mercruiser?

50 hours a year is usually considered typical pleasure usage. They'll easily go over 2000 hours IF properly maintained. I would consider 825 hours low for a 31 year old boat.

Have fun!

 

[Menace2Authority]

Re: New to inboards and have many ?'s

Is changing the water pump empeller on this motor basically the same procedure as this outboard video on youtube?

If it is, where do I look for exact model number so that I can order the impeller/gaskets?

http://www.youtube.com/watch?v=E-uzQi7IgwU

*Edit* Posted while 45Auto posted his response. Thanks for the links! they'll be extremely helpful.

Rob

 

[45Auto]

Re: New to inboards and have many ?'s

Go here, breakdown of your drive with part numbers is 6 lines down:

165 78-81

http://www.mercruiserparts.com/selectModels3.asp?type_id=DRA

 

[NHGuy]

Re: New to inboards and have many ?'s

Hey, and welcome. I have no argument with any of the previous posts. I do, however have a recommendation that you go find the post on homemade out drive stands and make yourself one. The hour or so you spend doing that will be saved many times over.

 

[vxtech]

Re: New to inboards and have many ?'s

reliability without question,recommend having spare belt,points on board aswell as knowing how to change both , 1st i/o for me with chevy 250 and love it

 

[Menace2Authority]

Re: New to inboards and have many ?'s

So this should have a mercruiser drive then I'm assuming?

 

[45Auto]

Re: New to inboards and have many ?'s

Never heard of a Mercruiser engine coming with anything other than a Mercruiser drive. However, since it's over 30 years old, there's no telling what might have been swapped around. You'll have to post serial numbers or pictures of the drive for any further identification.

 

[YeboGogo]

Re: New to inboards and have many ?'s

one note.
Change the impeller before the drive fluid. Otherwise you may be doing the job twice.

I recommend you drain the fluid, change the impeller. reassemble and then refill..