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Hey guys
looking for the low down on these old merc's. I have recently purchased a 2nd hand rig with a 115 hp inline 6 merc it has grey and red stripe on the cowl the engine serial number is OB380727 if that helps to identify the model. seems to be pretty well unmolstered old donk still running the autoblend oil mixing system and doesnt look butchered under the cowl.
she seems to have good compression and runs ok has a tonne of punch in the mid range and has the normal blue smoke of an old school 2 stroke at idle.
Well she is a bit before my time so for those with more experience "whats the low down of these oldies, the good the bad and the ugly" should i keep her or drop another 15G on a newie?
BigE
Nearly forgot I think it's an 89 model
finga
06-03-2011, 07:44 AM
The good:
They've got heaps of grunt courtesy of the inline 6.
They're fairly basic so not too much goes wrong
Reasonably fuel efficient if handled with respect...other wise you might as well shove a funnel on top of it.
Strong gearbox
The bad:
Corrosion in the water jackets. If they haven't been flushed well corrosion in the water jackets can kill them
Old...means parts and seals (especially) are starting to let go
Old school...some people just like new things
If something goes wrong with the carbi's balancing the 3 carbi's is an art form.
The wires to the black box seem to have let go of their insulation by now if they've been sprayed with WD40 all their live.
A complete rewire is normal at this age.
If you get a good one it's a good one. if you get a bad one it's scrap.
Other then that I would not part with mine and it's older.
A lot of people would scrap it and out a newer, lighter motor on though.
Has that one got hydraulic trim/tilt or just tilt?
Steeler
06-03-2011, 09:18 AM
All good points by Finga, do away with the mixer as the model you have was mercs first crack.
Good idea to replace the bottom crank seal every 500hrs or so if you have an engine crane not such a big job, just don't damage the bearing carrier they can be hard and expensive to locate.
Have the timing backed off a couple of degrees as these thing had a habit of detonating pistons.
Always found they ran better with Champion plugs L76's rather than NGK in them.
Finga if its the last of the inline sixes it will have the internal t/t not the external pump mounted in the boat.
As for replacing i would get a compression test done and these things will still run strong down as low as 95psi per cylinder as long as all are withing approx 7% off each other.
Seen a lot of these things buggered on the driveshaft spline so be sure to be liberal with the nickel anti seize if ever you have the gearbox off.
Like Finga said get a good one and your loughing but get a neglected one and well drop me a PM if you choose to dispose of it.
Finga
She' a trim & Tilt job the TT is internal. what is respectable fuel use on one of these babies?? I comming from a yamie 60 four stroke so i know i'm in for a shock.
Steeler
Thanks for the plug advice ( they look pretty old so i will change em)
What the best oil to use in them and if i pre mix is the ratio 50-1 ??
Thanks guys ( kinda like old school had a couple guys comment on the old girl whe they seen her )
finga
06-03-2011, 10:07 AM
At around the 3000-3,500rpm mark we get about 36 km per 25l in the ocean with our 90hp.
We don't push it outside because decrepit old me is the limiting factor/weakest link.
Full throttle dragging a couple of biscuits complete with a couple of young 'astronauts' wanting to be launched you can hear the tank go down.
Any pictures??
Finga
just for you Pic's
signature 1750L and 115 merc.
finga
06-03-2011, 02:36 PM
What a nice boat. You must be happy with that :)
Steeler
06-03-2011, 03:32 PM
I'm almost betting that motor was the original fitted to that " Real Haines ".A good friend of mine had the 1550R with a brownband 115hp and it handled like it was on rails.
Thats a top boat ya got there.
BigE,
You will be pleased to know that the last of the inline 6 Merc 115's were actually putting out 138hp at the prop!! So if she feels very punchy, you now know why..
50:1 fuel oil ratio if premixing. Premium unleaded fuel and never ever use stale fuel.
Knock the timing back a couple of degrees as mentioned and also fit one size larger main jets in the carbs. This will run you a little richer at high rpm and help prevent detonation.
These weren't issues back in that engines day as the fuel quality was far superior to todays fuels.
Enjoy!, they are a very good engine.
Yep
she was a "find" hull is sweet as. Just ordered a new multi rolla trailer to keep her on. Bloke at the shop said they have a side plate and main seal issue other than that there not bad donks just a tad thirsty.
Big E
Bottom seals can be an issue for any outboard really. When you do replace the 2 bottom main seals you can actually fit a third seal in there also which gives just a tad more protection from water ingress.
The inner sideplate is the main area of concern for the inlines. If you intend keeping the boat and motor for sometime and given its a healthy looking and sounding motor by your admission, it would pay to whip the powerhead off and remove the outer and inner sideplates. The plates should be reuseable, if not they are still available new from memory. Must be well sealed upon installation (including the bolts) as a water leak here puts seawater straight into the exhaust ports. And whilst the powerhead is off slip in 3 new bottom seals. New powerhead base gasket and you are back in business with only routine annual servicing to worry about.
Speaking of clean inline Mercs, I recently picked up an immacualte 115 Merc, 1982 model. Never seen an inline without corrosion on the trim rams or without corrosion on the tiller arm. Absolutely remarkably clean engine! Just ordered a used crank for it from the US ($500 landed). 1 piston and a few seals and bearings and she will be good to roll again. Bottom seal had obviously let go on this one causing it to fail when laid up. Apparently its lucky to have done 20hrs!!!!
Cheers
finga
06-03-2011, 05:14 PM
When you do the top and bottom seal do the cooling plates.
Doing the water jackets is a a bugger of a job if the motor is in.
Gees eh...the old trailer looks pretty spiffy as she sits.
Are you getting a new with brakes or is there rust in the old one?
Thanks for the seal info. are there any warning signs of seal failure i should be aware off? or is a roll of the dice.
The trailer had a rust issue in one rail wear a tie down was left on when wet and the gal has lifted probably a 1-2 foot sectin that needs attention rest of the trailer is pretty good. (new drop axle & Hyd brakes and single gal spring 1400kg) I'll on sell it to some one with time and skills to rebuild, good cheap project for someone.
BigE
BM
"""whip the power head off" ......... not a job for me i think. more of a battery drill man myself after that it's probably better if someone else looks at it. :)
Steeler
06-03-2011, 06:10 PM
Signs of corrosion on the bottom plug and tiny little beads of water.
thats a very well looked after boat mate. i have the same hull, a 1750c. They are a good engine. mine starts first go every time i turn the key even after sitting idle for a couple of weeks. The only issue with mine is the engine cannot maintain trim out position for long and i have to keep trimming it on the go every five minutes. This also means that i have to tie the engine up when trailering as it falls down. the bracket is useless and justs slips out. i have had it looked at and the seals replaced but was told was very hard to get the hydraulic piston thingy job so if anyone has got a spare and wants to sell?? Other than that its got some serious power and hole punch.
in terms of fuel consumption, they can be thirsty. I have a 120 litre fuel tank. i would use bout eighty litres of that for a 70km trip in generally calm, slightly choppy waters.
Steeler
06-03-2011, 07:10 PM
SI
get your hands on the longest old keel roller and slide over the ram when trailering.
Powerheads only basically 6 bolts and 2 nuts BigE!, but I hear ya..
finga
06-03-2011, 07:40 PM
Signs of the top and bottom seals getting hard is the motor gets hard to start when warm.
It'll still start well cold but not so when warm.
I have to do my seals and water jacket again very soon. As BM says...it's easy but it makes it very easy if you have the right gear.
SI
get your hands on the longest old keel roller and slide over the ram when trailering.
hey steeler, what ram is that? Sorry, i dont follow, was a big night for me last night. :P i have a bracket that just pops out but no through ram pin arrangment or anything?
Steeler
06-03-2011, 07:53 PM
If you have one of the later internal trim style rams you should have your trim rams and a power ram to take it all the way up.You should be able to slide over the trim ram a old keel roller and then lower the motor down til its resting on it.Better than tying it.
If you have one of the later internal trim style rams you should have your trim rams and a power ram to take it all the way up.You should be able to slide over the trim ram a old keel roller and then lower the motor down til its resting on it.Better than tying it.
yah, not too sure. i will post a pic. i dont think i can slide anything out of the way. cheers.
Noelm
07-03-2011, 09:42 AM
aaaahhh, the old tower of pwer, had a few on them in my day, a 135, and 115 X2, great engine, keep the revs up, they love RPM (and petrol) rust will kill that motor long before it blows up (hopefully) pretty simple engine in a lot of ways, yet complicated as well, try to find an old retired merc mechanic to look after it for you, for some reason, merc mechanics have a very soft spot for them. Not a lot of inherent bad points to them, keep good oil and fresh fuel and it will run for years to come. The old time mechanics used to have a saying ,not too sure if it is really anything but sales crap, but it went, "buy a Merc if you want to get there fast, buy a Johnson if you want to get there. . . and back"
Argle
07-03-2011, 11:16 AM
Had a 150 blue band on my old Stebercraft, went really well used heaps of fuel, blew heaps of smoke and was as loud as a jet (as you would expect).
Probably a one off but ours died when a gudgeon pin circlip let go and allowed the gudgeon pin to do a heap of damage to the bore:'(
Nice boat you have there - looks like she stays in the Ausfish fraternity
Cheers
Thanks guys for the info...... anyone else have any thoughts.
BigE
Steeler
07-03-2011, 09:11 PM
NoelM
But two Johno's one to get you there and one to get you back;D
Steeler
07-03-2011, 09:29 PM
SI
That brownband of yours should have 2 rams for trimming only and a power ram in the centre for when tilting the motor up for transit.Unless that motor has ( and this is off the top of my head ) a 2000 and later style replacement because the original shite itself you should be able to slide over a couple of old keel rollers over the trim rod rams when lifting the motor.
Note the trim rams either side or the power ram
http://cgi.ebay.com.au/Mercury-Mariner-Power-Trim-Assembly-NEW-RRP-3-671-/220727969711?pt=AU_Boat_Parts_Accessories&hash=item33646987af
adamleah
12-03-2011, 10:37 PM
Nice rig Ian ;) ....
When I had her I would get about 1km / litre when sitting on around 4900 rpm so if you stay lower on the gas you should get more ....... like someone said ,,, on one of the original services I had done on her, the mechanic told me that the model was actually a 135hp with a 115 cowling ,,,,,
The garage certainly looks empty now and the weather this morning when i rode past the ramp was glorious and I near had tears from missing her already. as I could have gone out !!!.......
Oh well at least you can take me out now !!!
Adamleah
I hear ya , was at work and wishin I was fishin. there always next weekend. bit the bullet and ordered a new trailer should arrive next week, ready for the big tow north (Bowen) in april. Mounted the chartplotter on Sat.
when's the pool party?
BigE
googarra
14-03-2011, 07:41 PM
Great old motor. They go like the clappers, whatever that is?
My saying on these motors, or any old outboard, is that they "rot out before they wear out'
If she runs well, just treat it right with good oil and maintainance and it will live up to its name.
They are thirsty, give it to them and 1km = litre can be expected.
If it is original and well looked after just leave it alone, as soon as you start dismantling and playing with it you will kill it with kindness
just my 10 cents
Thanks Googarra that seems to be the general consence if there good leave em alone and service them reglarly. it got great power for a 115 hp I'm sure it got more grunt than the cowl sticker. any one have any recommendations on the best two stroke oil to use in this style of engine?
BigE
Argle
16-03-2011, 08:26 AM
I used to use the Quicksilver oil in both my old 150 blue band and also in my 90hp Merc that was on the last boat. Seems a lot less smokey than some other brands I had used.
Cheers
yeah agree, you pay a touch more for it but does seem less smokey. more clarity and a rich blue. buying it in the larger volume containers will save you money in the long run with a thirsty dollar munching engine.
Noelm
17-03-2011, 07:17 AM
I was just thinking about the old in line 6 mercs I have had, and then I remembered the stupid cowl system they had, you almost needed a service manual to take it off! I would hate to try it out at sea in some chop! the early ones had a front cover, that was held on by a turn lever handle, with a push and turn action, then the middle section had a series of flip over catches, when this was removed, if you wern't careful, the top section fell off and into the water, it was only held on by a rubber locating thingy!
Very nice looking rig I wouldnt look at replacing the old merc until she starts costing you money
Argle
17-03-2011, 09:17 AM
I was just thinking about the old in line 6 mercs I have had, and then I remembered the stupid cowl system they had, you almost needed a service manual to take it off! I would hate to try it out at sea in some chop! the early ones had a front cover, that was held on by a turn lever handle, with a push and turn action, then the middle section had a series of flip over catches, when this was removed, if you wern't careful, the top section fell off and into the water, it was only held on by a rubber locating thingy!
Geez I had forgotten what a pain in the khyber that set up was!! I love the latch system on my Suzuki though8-)
Cheers
Noelm
17-03-2011, 09:32 AM
I reckon any other setup is better than the early Merc cowl latch system, a bit of rope or a couple of occy straps over the top would be better, when you see how it is done, it makes you think about the engineering that is inside the motor, if they went to that much trouble for a simple "lid"
Yep
I'm hearing ya with the cowl ...... seem like they didn't want the engine bits to get out or the tinkers to get in :) :) ...... Tin cowl just reminds me she's "vintage" .... whatever that means!
Any recommendations on an old school merc workshop who would understand there's no where to plug the laptop into.
BigE
They aren't as "old school" as you might think. The ignition system is fundamentally the same as ignition systems today across the board. Stators, triggers, powerpacks/cdm's and coils.
Large dealers will usually limit repairs and servicing to engines about 10 yrs of age or younger. The reason for this is they are easy to work on so therefore easy money. If you find an independant mechanic (not holding a motor franchise) he will likely be happy to work on your engine.
Alternately, learn to work on it yourself if you are mechanically inclined. You would be surprised how little is actually involved in a routine service.
Cheers
You've got the easy tin cowl BigE, the earlier clamshell cowls were a real work of art.
Give it a WOT run from time to time and if you ever see an unexplained decrease in WOT RPM get it checked out straight away.
If you decide to do any work on it yourself a genuine manual will be worth its weight in gold.
Noelm
18-03-2011, 08:58 AM
AH, Gees I have some stories about those old motors, some very funny now, but scared the sh!t out of me at the time, everything from fires to flooding carbs.
Hmmmm Fires you say? .... do they go faster on fire? I must say the fuel pan under the carbs does have me worried. ........... how much was that fire extingisher at boat shop?
BigE
The fuel drip pan is there to catch the fuel that spills from the carbs when the motor is trimmed right up in the trailering position.
aaaahhh eighties engineering excellence. :) (fuel drip pan)
Fed i think mine is the clam shell type cowl, cover at the front and 3 cam lever latches then manouver it all over the top of the engine ( there a reason it called a TOWER of power) hate to be doing it outside in the rough.
Come on Nolem give us the war stories (cringe)
BigE
BigE, any current carby engine (any brand) will still have a device for catching fuel that comes out when tilted. Hidden inside the air silencer though these days but certainly still present.
The clamshell covers weren't used on the inline 6 engines. A clamshell cover hinges at the rear of the motor and is made of fibreglass. The front cover lifts off, then a couple of latches undo and allow each side to swing open. The top and sides are one piece.
Trouble you may encounter with your engine is the stator (common Merc issue) and powerpacks. Alternator is fairly robust unless you reverse polarity connect your battery cables. Triggers almost never give trouble.
Good quality oil, fresh premium fuel, annual servicing and it will last you a long time.
cheers
Thanks BM
my cover doesnt have a hinge at the back , it just springs open and falls over the side. luckly there is plenty of latches with hooks to catch on things on the way down so you dont lose it all together.
BigE
lol :)
Ideally you shouldn't be taking the cover off on the water. Keep her serviced like any engine and she will be reliable.
Chimo
19-03-2011, 07:59 AM
So you're awake BM!
C
C
Yep. Kids are awake at 6 mate!
Rest assured BM i'll keep her serviced. like all things mechinical they rarely brake in the shed at a convient time when you have a mate to help, all the right tools, and some spare cash to burn. :)
noticed a pull cord in the front cover of the cowl ....... has anyone even tried to pull start one of these suckers.
BigE
They are relatively easy to pull start.
Manually set the choke at the engine (black knob protruding from the top of the front plate), raise the warm up lever right up and give the cord a good hard yank.
Usually will start within a couple of pulls.
Even the V6's have pull starters.
cheers
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