mercury 1150???

[Innovator1]

I am new to the board and currently looking at a 1977 Hydrostream Viper with a Mercury 1150. The owner was telling me that it is a 150hp. Is that true? or is it a 115? He didnt know the year on the motor, but it came on the boat new, so I am guessing it is a 76 or 77 motor. What gear ratio would it have?
Also, is there anything I should look out for on it? Signs of it being bad, etc? Thanks. Any input anyone might have would be greatly appreciated. Thanks again.

[Raceman]

Hi Innovator. Welcome to S & F. If you post the serial number on your engine somebody can tell you what it is, assuming the serial number on the powerhead (starboard side about even with the centerline of #5 cyl) matches the one on the swivel bracket. If you'll post a picture I can tell you the year by the stickers assuming the cowls are original.

In the mid 70's there were both 1150's and 1500's, and there was a fair amount of performance difference. The 1500's had holes in the sides of the pistons and corresponding trenches in the cyl walls which Merc reffered to as "power ports" and also had higher port timing. In the 80's, the 1150 became very close to the old 1500, with Merc's change to a net horsepower rating, but in the 70's there was a definate difference. The 70's 1150's had a lot more low end and were stronger through the low mid range than the 1500's, but were pretty doggy on top.

The old 1.78:1 gear ratio went away after 71 and if your engine is as new as you think, it'd definately be 2:1 unless somebody put a gearcase off of an older engine on it.

As far as what to look for, a compression test is a good place to start. The engines are very durable if run on super unleaded, minimum 40:1 oil (although I prefer 32:1) and have good waterpumps always. If it is an 1150 it's not quite as prone to burning pistons as the 1500's are. If it's a 1500 you'll want to make sure it turns a minimum of 5800 RPM at full throttle. Lugging em with too much pitch under full load makes em have a tendency to burn pistons also.

[SeaJay]

Hello Innovator and Raceman. There is a web site (www.obparts.com) that has listings of beginning serial numbers for each year for various model Mercury and other other brand outboards. For Raceman: what year in the 80s did Mercury change the way they rated the engine Hp so that one would know if the 115 Hp, I6, merc, he is looking at, is one that is closer to the 70s 1500 in performance? SeaJay

[Raceman]

SeaJay, I can't ever remember when the change was made. The newest inline I've ever owned is a 78 1500XS and I lost interest in em (temporarily) at the time the V6's came out. I remember my friend at Merc telling me that the "new" 200 was the same as the "old" 225 which was NLA, but just can't remember when................. 82 or 83 would be my guess, but it's just a guess.

[Innovator1]

Raceman, The guy who has the boat for sale is best friends with the original owner. He said the motor is original, but was rebuilt about 20 hours ago. He also said that with a 28" pitch cleaver it was clocked at 86 mph. Does that seem about right? Thanks for all the help thus far. I'd just like to know what I am buying before I get into something that I won't ever be able to get out of (I know everyone has been there, done that at least once). Thanks

[Raceman]

Well, there's good news in the picture. That's a shortshaft engine and Merc never made a short 1150 except in 1972. The stickers are an accessory item, offered by Merc sometime in the 76 to78 time frame. If they were different shades of blue with that same shape they would be 76 or 77, but by then Merc only built the high perf XS in the shortshaft.

There are several things we can look for here: 1st, the bolts that tighten the clamp brackets to the transom at the top had plastic T handles in 74 and earlier and changed to hex, like you'd use a socket on in 75. The fuel pump amounted to 2 pumps on the side of the block in 73 and earlier and there was only one in 75 and it was mounted on the pan. There seems to be some doubt as to 74 and for right now I think it could've had either type.

If the engine is a 75 or newer and originally short shaft, it would have a J stamped in the block in the area of the casting number on the right side (starboard). The serial number is even with the centerline of the #5 cyl and the casting number is slightly above it if I remember right. If there's a J there, it's a high perf powerhead that was actually rated at 155 horsepower. The J's first came in 75 and followed into all the XS's from 76 to 78. This engine, beginning in 76 would've also had low water pickups, UNDER the gearcase torpedo, as opposed to the general holes in both sides above it, and would've had a louvered cowl when new.

The first thing I'd do is see if the serial number on the side of the powerhead matches the number on the sheet metal plate on the front of the engine. If it does, and the engine has the hex bolts, then it's pretty much gotta be a J engine.

Regardless of what the engine is, that boat won't run 86 with an inline. The boat would probably be pretty easy to get to run 75. Somebody with some real raceboat setup experience might get it to 80 if the engine is in excellent shape. 86 is pretty much out of the question. An awful lot of speedo's are that far off on the top, so the owner may believe it himself.

[Raceman]

Incidentally, that's a really well balanced and fun combination. If the price is decent and it's in reasonably good shape, I think you'd really have fun with it. Crazy Horse, who obviously hasn't seen this thread yet or he'd be commenting, has a similar setup that he bought new in the mid 70's and he's still "crazy" about it.

[Tower of Power80]

Hello Raceman
I have a 115 ADI from 1983 and there is also J stamped in the cylinderblock.
I this also an Highperformance engine?


Richard

[Raceman]

That's a new one on me. The XS engines ended in 78, although I think the high perf division still sold em another year. That was the end of Merc's offering a high perf inline. I don't know what the J on your block means, assuming it's the original block in that engine. I'm also not sure if a pre-ADI powerhead could be substituted in an ADI type engine without machine work or adapting.


I think Jeff Grigg probably knows a lot about those engines, in addition to the older stuff. Maybe he can say for sure.

[Jeff_G]

I have never seen a J on a ADI block, but then again I wasn't looking. I would suspect it had more to do with porting and power porting specs than anything. The ADI blocks used a different casting from the dist blocks so unless someone from Mercury could tell us that would be my assumption.

[Innovator1]

The owner just emailed me and said the only numbers he could find were on the #2 cylinder and they read as follows: 10235068.
Does that mean anything? Or are they the wrong numbers? Thanks

[Superdave]

I had one, but it was a mismatched front half.;)
Dave

[Raceman]

Innovator, here's a picture of the right side of a 75 model std length 1500. It's very original and I don't think the powerhead's ever been out or re-painted. If you'll look by the number 5 cyl (which is 5th from the top) you'll see the bare area where the engine serial number is. This is the bare stripe that's roughly even with the back of the fuel pump in the picture. There's also a casting number just above it in the black recessed area. That's where the J would be stamped. Any 1500 that's 74 or newer would have this style fuel pump too.

The bottom line is, if that boat's in decent shape and the price is okay, I'd buy it. Shortshaft inlines are getting harder to come by and that makes that package somewhat unique. I'd be more concerned with condition and price than specifics, but unless somebody's pulled a switch with some parts, it's almost gotta be a 1500 anyway.

Did you ask about the shape of the bolts at the top of the clamp brackets where the engine mounts to the transom? T handle or hex??????