info on 165 hp mercruiser engine and leg

Ironside

Petty Officer 3rd Class
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Nov 12, 2004
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75
Hi I am a new boat owner "inherited my grandfathers boat" and am looking for advice on upkeep and matenance ,tune up info or any advice on this engine leg ext<br />Thanks
 

Don S

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Re: info on 165 hp mercruiser engine and leg

Before you do anything to the boat, get a Mercruiser service manual for your engine and outdrive. It will save you a lot of trouble in the long run.<br /><br /> Mercruiser Website
 

Ironside

Petty Officer 3rd Class
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Nov 12, 2004
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Re: info on 165 hp mercruiser engine and leg

Thanks Don I'll get one especialy on the leg .The motor is easy ,I am an automotive mechanic but the transmission and leg will be the challange
 

Bondo

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Re: info on 165 hp mercruiser engine and leg

am looking for advice on upkeep and matenance ,tune up info or any advice on this engine leg ext
Well,<br />With All the information that you've shared with us, I'll venture a Guess............<br /><br />You've got a Mod.1 outdrive behind a 250cid Chevy I-6 motor.....<br />Maybe up to a late 70s driveline......<br />Or,<br />Possibly, If it's a I-4 motor, it Could be 1 of the Dreaded Merc. 470s..... with Either a Mod.1, or an early Alpha 1 drive........<br />I Think that Merc. gave that motor a 165hp badge in 1 year or another.......<br /><br />You should get Much More Specific with your Questions....... Or, just surf the boards,+ Learn from previous posts..... <br />There's a Search Button at the top of Every page.... Use It....<br />DonS has posted links on Many different threads here at iboats..... Click on Every 1 of them,+ Learn what Parts,+ other Things are Called......<br />That way we can all speak the same Language..........<br /><br />Personally, I'm here to Help you, Any way I can.....<br />But, I'm a 1 fingered, Hunt,+ Peck Mechanic............................... :D <br /><br />Good Luck,+ I'll see ya around................
 

rodbolt

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Sep 1, 2003
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Re: info on 165 hp mercruiser engine and leg

hello<br /> not meaning to be mean or anything but, the very first thing ya gotta do to work with a marine power plant is forget everything you do as an auto tech. lets face it. when was the last time you solved a high speed lean condition after 20 min above 4000 rpm?<br /> be truthful here.and please answer that question.<br /> most automotive techs royally screw up marine stuff.<br /> cause they think they know and it looks rather similar.<br /> so take my advice and Dons's advice. get a manual and study how why and what is this package trying to do.<br /> as far as the "leg" also called an outdrive by those of us unfortunate enough to do this for a living. gears is gears<br /> it does not matter if they are in a 8 sec camero or a 5 ton truck or a lower unit. they all have the same specs to live by.<br />so get the manual and post us back. but if you have no experience with high performance equipment that runs at its rated horsepower for hours on end forget everything ya know and relearn it.<br /> good luck and keep posting
 

Don S

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Re: info on 165 hp mercruiser engine and leg

most automotive techs royally screw up marine stuff.<br />
Now, now you guys......I have you know the auto mechanics in our area do a fantastic job for us. So far we have done complete repowers (after the engines blew up), rebuilds (gas and diesel), numerous outdrive re-rebuilds, replaced automotive parts (distributors, fuel pumps,starters, alternators, etc.)with marine parts. Basically just fixing problems they caused. And all at the unknowing customers expense.<br />They are the best salespeople out there for a real marine mechanic, plus you don't have to pay them. :D :D :D
 

Ironside

Petty Officer 3rd Class
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Nov 12, 2004
Messages
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Re: info on 165 hp mercruiser engine and leg

Thanks guys <br />I am in route to a boat shop tail between my legs to get the proper manual<br />it should be great fun learning and cursing some marine mechanics
 

JustMrWill

Master Chief Petty Officer
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Aug 12, 2003
Messages
877
Re: info on 165 hp mercruiser engine and leg

Welcome Aboard!<br /><br />Nobody here is telling you that your knowledge is worthless...just to be wary. I (as well as most people here) have wasted money on an automotive part before realizing that there is a difference (other than the 2x cost!!) We all just want you to know..when in doubt - ASK! Use your knowledge of the inner workings and problem solving...just keep in mind that there are MANY differences in performance, stress, corrosion resistance etc that come into play with a marine powerplant.<br /><br />Enjoy your new "hole in the water".<br /><br /> :)
 

Doug Durako

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Nov 17, 2002
Messages
519
Re: info on 165 hp mercruiser engine and leg

Glutton----one more tip----get serial numbers on your motor and drive and most any part you ask about here. Lots of boats are put together with pieces from different years, especially if they were built during the "model year change."<br /><br />There is a hull number stamped on the stern of the boat which will tell you the model year. Drive and motor may be from the previous year or earlier.
 

kennym5422

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Nov 14, 2004
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Re: info on 165 hp mercruiser engine and leg

Glutton<br /> I agree with Don S Get a Merc service manual and learn about the outdrive, ie the waterpump, u-joints and changing the gear oil. Also if the boat has not been used in a while and it is a 70's check the fuel in the tank and the belows on the outdrive and manifold. Also a company called Pertronix makes a great electronic ignition conversion that fits your distributor and you can kiss those funky points and condenser goodbye.
 

Ironside

Petty Officer 3rd Class
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Nov 12, 2004
Messages
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Re: info on 165 hp mercruiser engine and leg

Thanks guys I got my manual yesterday and am currently reading up before i get out the wrenches great tip on the distributor thanks ricochet does that dist upgrade require recurving or is it ready to go?
 

Don S

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Re: info on 165 hp mercruiser engine and leg

The Pertronix conversion only replaces the points and condenser. The advance curve is done by mechanical weights in the distributor below the points plate, so nothing should change in that part of the distributor.<br />Did you get the Mercruiser manuals (2 different manuals) for both the engine and the drive?
 

Ironside

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Re: info on 165 hp mercruiser engine and leg

No I got a manual from a boat shop here that covers 1970 - 1989 many different motors and four or five outdrives
 

Don S

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Re: info on 165 hp mercruiser engine and leg

No I got a manual from a boat shop here that covers 1970 - 1989 many different motors and four or five outdrives
Sorry to hear that.
 

Ironside

Petty Officer 3rd Class
Joined
Nov 12, 2004
Messages
75
Re: info on 165 hp mercruiser engine and leg

Bad idea? not good info .I finaly found the number on the leg serial #8569912 does that tell me what out drive it is and is the manual i got unsatisfactory for repair? It is Clymer Mercruiser stern drive shop manual 1964 - 1985<br />as per the screen name im ready to be off one step to the left again <br />thanks
 

tommays

Admiral
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Jul 4, 2004
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Re: info on 165 hp mercruiser engine and leg

g<br />i no that the merc manual will be compleatly about your motor and drive and not side track you with things that cover a 20 year period<br /><br />also some people say they are not for written for DIY people but i find that there methods to solve problems are very easy to follow and very compleate<br /><br /><br />tommays
 

biloxiriver

Petty Officer 1st Class
Joined
Aug 20, 2002
Messages
256
Re: info on 165 hp mercruiser engine and leg

Having recently survived the pros and cons of an inline 6 cyl, 165 mercruiser of early 70's version, I have just a few recommendations:<br />1. Make sure there is no flex in the transom; you can test this buy grasping the outdrive and trying to move it. If the transom flexes at all, you will probably spin your drive coupling. I did this twice before finally figuring out that the transom was flexing. Replaced 2 drive couplings and totally rebuilt the transom. Very expensive lesson.<br />2. Change the water pump in the outdrive. It is do-able on your own, but the manual is really important to doing it right. Also, YOU MUST MAKE SURE THAT THE DRIVE IS IN FORWARD BEFORE STARTING REMOVAL AND THAT THE DRIVE STAYS IN FORWARD FOR REINSTALL. My manual did not tell me that, I had to learn it the hard way. This is not a difficult job but is a two-person job. Follow the torq specs closely. Poor torq will result in the new water pump coming apart.<br />3. If the motor has been ran in saltwater, or even just sitting for several years, I would replace the manifold and riser. Luckily the exhaust manifold and riser are easy to get to, at least they were on mine, and except for being heavy are easy to replace. Use some liquid soap to lossen the exahust belows. My manifold system was easy to remove even after years of saltwater exposure.<br /><br />Personally, I found the 165 with inline 250 a good set up and it pushed my 20' Wellcraft along pretty good. The engine was strong and durabl, and was easy to work on. Good luck.
 
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