TOPIC: Questions on a couple Mercs

I have been looking at adding a little more power to my Uniflite and have found a couple motors. One is an early 70's 115 with no power tilt, has about 300hrs on it. The other is a '79 140 with power trim. This one has about 30 hrs since a rebuild.

1. I have never had a Merc and am wondering what the pros and cons are over say an OMC

2. Can the 115 be given a bit more HP? and add power trim?

3. Anything special I need to be on the lookout for with these motors?

30 hours or 300 hours,...proper maintenance, proper oil & additives, proper gasoline, & RPM use, all will have played a role in which of the two motors is in better condition internally.
If they have been rebuilt - who did the rebuild & what exactly did they do can make a big difference in what longevity the beast is likely to have.

Yes,...You can add power trim to an early '70s 1150.

By "early '70s" you are including (2) models of an 1150.
The '70-'72 that can be turned into a powerful 1350, but the '73-'80 1150-115 is pretty much what it can be without a machine shop & lots of specs.

The '78 1400 thru '80 140 are probably among the strongest of the inline-6 Mercs, second only to the '73-'77 1500.
IMHO,...The '81-'88 115 inline-6 is the best overall choice for pleasure boating. They have low dome pistons that are more forgiving than the earlier high domes, but still provide an unbeatable horse-power to weight ratio.
The 79.5 through '88 inline-6 Mercs also have an alternator driven ignition system (adi), which is less likely to leave you 'ignition-less' out on the water than the earlier 900s, 1150s, 1350s, 1400, 1500, etc.
With the adi fired beasts, you can experience a number of different ignition related failures, and still have some of the cylinders firing and able to limp you to port.
If you do a lot of salt water boating, I find that only a few of the late '80s inline-6 Mercs are internally protected, and if not, typically will not come apart eventually when internal repairs are needed. In the '90s Merc began doing a much better job in this category.


I do love my inline-6 Mercs.
Attached are pictures of my latest Cloud White Frankenmerc.
'61 800FGS cowl wrap, lower pan, and drive shaft housing, early 650-4 cyl lower unit, mid-'70s power trim, topped by an 800DR top hat.
The powerhead is a '64 1000, with '68 1000ss crankshaft, mains & end-caps, 1000ss stator, starter & flywheel, 1500 distributor, cdi/rapair ignition components, and a v6 regulator with built-in rectifier.
Doc

OH YEA !!!!!!!!!!!!!!!!!!!!!!!!!!1

dave bernard wrote:

OH YEA !!!!!!!!!!!!!!!!!!!!!!!!!!1

^^^ sort of like saying crack cocaine can be addictive...

IMO, much more accurate:
OH HELL YEAH!!!!!!!!!!!!!!!!!!!
There, now I feel better

Excellent work Dr. I've got a late 60's 650 and an early 60's 700 I'd love to be able to afford your level of expertise on a rebuild of either. Really spectacular franken-Merc motor.

Not sure why, but the text editor isn't allowing me to increase the size of my text. It was supposed to be:
OH HELL YEAH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! in the largest font available, didn't work..............

Thanks everybody

Hopefully I answered Nick's questions and didn't totally steal the thread.

doc

Steal away DOC! I gotta stop soon and see just "what ya been up to lately shops" Plus ya gave me a idea...got a email coming big guy!

And my avatar was a 115, crank up rebuild Doc, to a true 135. Trust me.."he (and others here) damn sure know "Merc Stacks!"

Hey thanks for the input guys. The 115 I found out is actually a '79 and the 140 is a '78. Going to look at the 115 tomorrow hopefully and the 140 the day after. Any easy way to tell if the 79 has the ADI ignition? The boat sits on a trailer the majority of the time and its all fresh water here so no major corrosion issues. The 140 is going to be around $1000, the 115 the guy is willing to negotiate a bit so I'd guess in the $600 range. These prices sound reasonable?

Sounds like both Mercs could be nice scores - if they pass compression tests. Granted,...Compression tests can be very deceiving as to internal condition, and additional leak-down tests can be beneficial, but don't always answer the internal condition story.
The ADI motor will not have a distributor. It will have (6) coils, each one with a spark plug wire going to each spark plug.
doc

Thanks Doc,
Those are some amazing motors you build. I have always liked the look and sound of towers. Hopefully one of these will work out for me.

Well I ended up getting the 140. Its in excellent shape. Traded some labor for it, worked out pretty good. A couple more questions it's a 25" shaft and my boat has a 20" transom the cavitation plate is going to be about 4" under the bottom of the boat, is this going to cause any major issues? And for farther down the road I love the look of the older mercs with all the chrome, can the back plate and cowling be changed out to this style?

Far as I know they never made a 140 XLS Inline. Perhaps you have a 20" mid-section with a 5" aftermarket extension kit installed. If so, you can remove the kit and restore the motor to a "normal" 20" transom height. The XLS hanging down there will cause a ton of drag and spray, along with highly undesirable handling characteristics.

If you like the chrome bar that's on the older tophats, you could probably adapt one to your motor's top. Wrap-around cowlings and front faceplates are pretty much interchangeable with early 1150's, 1250's & 1350's. Cowlings from the older, smaller hp Inlines (90, 95, 100, 110) are a bit shorter and you might have issues with those. You can get "retro" decals and re-do your existing pieces. For the lower cowl, you might be able to adapt the wrap-around chrome strip from an older motor. I think the cowls are pretty much the same size.

Anyway, Hope that Helps, let us know what you find on the XLS issue; a pic might help, too.........ed

On closer inspection you can definitely tell that it has some sort of aftermarket extension. The extension paint is the only paint that is flaking off. So the real question is how hard are these things to remove? Do I need an entire drive shaft or is it just a 5" adapter piece for the drive and shift linkages?

If it is an extension it will have 5 inch extension shafts for the shift linkage and the drive shaft, these just come off as does the 5 inch block extension. The water tube will also be longer, this you can cut to length using a copper tubing cutter. Just remove the same amount as the height of the extension block.

I have wood, ok sorry but Johnson really

Nick, see if you can post a pic of the lower extension set up and the rest of the engine. You can probably sell the extension parts on ebay, they are getting harder to find, also not used as much but there is probably somebody out there that wants to turn a short shaft into a long shaft.

I like the Merc 4 or 6 it doesn't matter but Doc that is a nice backrounds of all nice mercs,I have a lot of mercs but they don't get done til we need them looks good Bill

Bill,
I've got my 'fair share' of unrestored Mercs myself

Sometimes it takes a half-dozen or more of them to find enough good internal parts to properly rebuild just one, so 'extras' are always welcome in my Mercury Magic Shop.
The first picture shows the pile of dead parts that piled up during my latest hunt for sweet internals for a couple Super Thunderbolt builds.
The second picture shows one crankshaft assembly awaiting rings, and another crankshaft awaiting cleaning and final inspections of the (4) piston & rod assemblies selected for it.
The most prevalent cause that damaged the rejected parts included pistons and blocks is damage caused by failure to keep a good water pump installed.
The other primary cause of defect to the connecting rod journals or crankshaft journals is the presence of moisture - whether ambient during long times of the motor not being used when not properly fogged or stored, or due to water intrusion of the crankcase area caused by either cracks in the block, corrosion holes between the water-jacket and the exhaust or combustion chamber, or failed gaskets or seals. It really sucks to get down to the last journal on an otherwise sweet crankshaft and find the journal of the crankshaft etched from rusted needle bearings.
Fun stuff BUT well worth while when I finally can return one of these sweet little jewels back to life.
Doc

Well guys got the lower unit and extension parts out of it. Put a new impeller in before it got too dark out to do anything. When re-installing the lower unit are their any tips and tricks you use to make it any easier? I've heard some guys say it has to be in neutral, others say forward. This is my first shot at the merc stuff so I hope I dont screw anything up.