Mercruiser Inline 6 Cylinder 165 HP - The beginning.

MercMonster

Petty Officer 2nd Class
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Jun 3, 2007
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I just bought a 1976 Ebbtide Riviera yesterday and got to really go over the problems today and now I'm here for many, many questions. This is my first boat and it does have some problems. Maybe major ones. And I'm okay with that, I think:)

Let me get you familiar with my boat first off. Engine is a Mercruiser Inline 6 cylinder 165 horsepower. I don't have a whole clue about the outdrive yet, but do know its a mercruiser, like that helps. I was told by previous owner the engine overheated and that the head gasket was blown. "All of the fluids were drained" and there is new oil in the engine. The battery is toast, so going to get a new one this week. So don't know a whole lot about the electronics other than when I tried to jump the battery to check to see if the engine would turn, I heard a whining noise and unhooked it when I heard that. Later found out that the transom outdrive lift was turned on and the outdrive was lifted off of the support I had it on for transport. So that seems like hydraulics may be half way good anyhow, huh? There are several wires either lose or corroded where I have no idea where they go. The gas line was cut for some reason, so I have to replace that. My biggest concern right now is that the head or block may be cracked. There IS evidence of it overheating by the Merc serial number tag being heated and shrunk to half its normal size and the plastic clips that hold the alternator wires up to the manifold have melted free. That's what really worries me. That it got that hot. I'm afraid the water pump is shot - quite a bit of rust in those crevices after removing the hoses for a peek - maybe this is normal for the water lines in a boat? This is a solid boat. And only one slightly weak spot in the whole floor, which is wood. Mid seats will have to be repaired and am hoping to design and build those myself - Something new to learn - Other than that, she's a keeper.


My first question? My friend tells me he hasn't heard of any of these engines "blowing a gasket". Is it really that rare that it happens on these engines? Am I more looking at a cracked head or block? What can I do to check for this. Will compression test check for this? I hate to replace a bunch or parts to get the thing running and then have to take them all back off again to put on a new engine. Where do I start?

Let's slip one more small question in this post for someone that can maybe help me with something else. There is a small metal hose coming off the carb to the manifold. That hose has been eat through with rust. Does that hose unscrew out of the manifold or do you have to take the manifold off to replace that part. Whether I replace the engine or not, I'd just like to know for future reference

Oh, why not one more question... How difficult is it going to be to find parts for this boat/engine/outdrive? Just curious.
 

ziggy

Admiral
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Jun 30, 2004
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Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

i'd start with a compression test. go forward from there. the metal tube going into the manifold is the preheat tube for the bimetel choke. a year or so ago i was able to get that tube from merc. just drill out the reminets of the old one. well, i guess i drilled out enough to get the new one in. after i cut it off a bit. it did warm up and pull the choke off though......it just sits in a holes in the manifold that allow it to get hot fast so it heats up the choke coil..........get a oem service manual.......
 
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ziggy

Admiral
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Messages
7,473
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

IMG_1330.jpg


that tube to the right of the carb base is the preheat tube.....
 

MercMonster

Petty Officer 2nd Class
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Jun 3, 2007
Messages
151
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

The tube that went down there from the carb was smaller like it fit inside of that tube. What I have left looks like that, only not so shiney. Then there's the smaller tube that rises to the carb. If I swing the small tube around to line it up, there's about a hair's width from one to the other, where it rusted in two, I'm guessing. The heat rising from that tube is what heats it up? Could I just buy a piece to fit down inside that one? Or just leave as is? Or is that a "sealed" line to the carb??
 

MercMonster

Petty Officer 2nd Class
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Jun 3, 2007
Messages
151
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

Should have stated (forgot) there is a braided white hose cover on the thin tube up to the carb. - For help in identifying earlier -
 

ziggy

Admiral
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Messages
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Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

ok, my memory is comeing back a little now. yer right. that tube in the pic is part of the manifold. the tube ya got that rusted thru, is the replaceable one. thats why i got away with drillin my old one out. drilled into the tube in the pic far enough to accept the new one. the other end screws into the auto choke assembly....

The heat rising from that tube is what heats it up?

yes. that's an exhust port that tube is crossing thru.....preheat air to warm up the bimetel strip in the auto choke to pull it off choke......
 

MercMonster

Petty Officer 2nd Class
Joined
Jun 3, 2007
Messages
151
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

get a oem service manual

Got a good source for one? Any other manuals that are helpful for working on this boat? Also, would like to know how to ID the outdrive. Anyone can help there?
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

i'm pretty sure ya need merc. service manual #2. C-90-71707.

got mine off ebay. one of the few things i've bought there. and it worked good for that too....i think ya can get it new from mercuriser too....pretty pricey though....

how to ID the outdrive.
look at. know which outdrive i have.

http://www.mercstuff.com/howdoi.htm
 

MercMonster

Petty Officer 2nd Class
Joined
Jun 3, 2007
Messages
151
Re: Mercruiser Inline 6 Cylinder 165 HP - The beginning.

Thanks for that! Looks like a TRS-280. Okay, which brings me to another quick question. Does the outdrive run with transmission fluid? I have a clear tube with what looks like red tranny fluid, but I'm really new to boats, so..... Also, what was used to lift the outdrive when the battery was being jumped. The one where the switch was turned on?? Hydraulic fluid or what? I have a small black box with a bolt missing from the corner of it. Looks like some sort of fill hole, but what fluid is that for?


As for the book...I was just looking on ebay when I saw your reply. Now that I know which one to look for, I'll see if I can find one.
 
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