Found my old Mercury 7.5HP Outboard today

[Tremlett 15]

for info 1980 > 82 decals

 

[jfm]

Tremlett
the serial no is 9236651, made in Belgium. Its black with grey / red stripes on the side with "MERCURY" in white capitals. It has a white 7.5 at the back.

Just off now to get some 2 stroke oil. 2% mix I think isn't it?

Hmmm. Strange. The serial number suggests 1979 as per the Swedish merc geek database, which is I imagine what VicS uses. That database has errors though.

The decal you descrtibe is most certainly not 1979., The 1979 decals were unusual, no-one like them and Merc only used them for that one model year. They had a blue band, but it was sort of blue at the aft end of the band and faded in a (pixelated way) to black at the front end. The word mercury was in a naff font, all lower case, with the e written as "e" not "E" (1978 being the only other year in Merc history that e was used instead of E)

If your decal is a horizontal band with stripes coloured (bottom to top) light grey/darker grey/almost black/thin red/black, and MERCURY in white upper case, and no blue anywhere, then it is a 1986

EDIT - I see tremlett has just posted a pic of the naff 1979 decals with the faded pixelated pattern while I was typing that! Tremlett can you post a pic of 1986 that I describe in the para above?

 

[jfm]

for info 1980 > 82 decals

Tremlett that's mostly correct. They were 1980 to 83, not 82. The next set were brown, and they started in 1984. Also, during the period 1980-83 there were subtle differences to ther decals used on the front twist-and-remove cowling on the in-line 4s and tower-of-powers, that give away the diffreences between those years. That's quite important when buying old motors becuase 81 was the first model year when they rated hp at propshaft not flywheel, and what Merc did was sell 90, 115, 140 in-line 6s in 1980, then sell 90 and 115 only from 1981 onwards, and what actually happened was the 115 was rebadged 90 and the 140 was rebadged 115. So there's quite a difference between a 1980 and 1981 115hp.

 

[Tremlett 15]

Tremlett that's mostly correct. They were 1980 to 83, not 82. The next set were brown, and they started in 1984. Also, during the period 1980-83 there were subtle differences to ther decals used on the front twist-and-remove cowling on the in-line 4s and tower-of-powers, that give away the diffreences between those years. That's quite important when buying old motors becuase 81 was the first model year when they rated hp at propshaft not flywheel, and what Merc did was sell 90, 115, 140 in-line 6s in 1980, then sell 90 and 115 only from 1981 onwards, and what actually happened was the 115 was rebadged 90 and the 140 was rebadged 115. So there's quite a difference between a 1980 and 1981 115hp.

Hi jfm

only going by what I have

 

[VicS]

Hmmm. Strange

It is strange. There is also a year identifier on the Brunswick marine download site. That does not list any Belgium made models for '79, '80. '81' 82 or '83. they resume with 9416176 for 1984.

The quoted number must be during the period '78 to '83 (9167506 onwards for 1978)

Id say that its the model number that counts rather than the decals esp if the motor was bought second hand. It could have later cover fitted and been dressed up as a later model than it really is.

 

[Tremlett 15]

It is strange. There is also a year identifier on the Brunswick marine download site. That does not list any Belgium made models for '79, '80. '81' 82 or '83. they resume with 9416176 for 1984.

The quoted number must be during the period '78 to '83 (9167506 onwards for 1978)

Id say that its the model number that counts rather than the decals esp if the motor was bought second hand. It could have later cover fitted and been dressed up as a later model than it really is.

yes VicS, on my lists, one shows blanks & the other gives 9181726 > 9461525 Belgium 1978 > 1984, odd.........

 

[Tremlett 15]

Tremlett that's mostly correct. They were 1980 to 83, not 82. The next set were brown, and they started in 1984. Also, during the period 1980-83 there were subtle differences to ther decals used on the front twist-and-remove cowling on the in-line 4s and tower-of-powers, that give away the diffreences between those years. That's quite important when buying old motors becuase 81 was the first model year when they rated hp at propshaft not flywheel, and what Merc did was sell 90, 115, 140 in-line 6s in 1980, then sell 90 and 115 only from 1981 onwards, and what actually happened was the 115 was rebadged 90 and the 140 was rebadged 115. So there's quite a difference between a 1980 and 1981 115hp.

jfm, was it not a few years later that the hp rating changed, I dont know the year but my 500 50hp became "45hp classic" model, was not closer to 1986/88 ????

 

[jfm]

Ah, thanks Tremlett. I stand corrected, I think! Your pic shows the subtle difference between 1980-82, and 1983, and that's actually one (there are more) of the "subtle differences" I referred to. But to be very precise your earlier post did indeed show a 1980-82

So far as OP is concerned, the grey one I was referring to is 11th from top, which dates his engine at 1986-88

This is way too geeky. Better stop now

 

[RIN]

Id say that its the model number that counts rather than the decals esp if the motor was bought second hand. It could have later cover fitted and been dressed up as a later model than it really is.

You may well be right there. It was sold to us as reconditioned but I suspect the only reconditioned bit was the case. Here is pic I took this morning.

Anyway, I cleaned out the telltale pipe and got this which I was pleased with

The problem being that I broke the fitting that secures the pipe to the engine block. This has a thread that fits on to a housing above the engine blok. You can see the hole it comes from under the spring in this pic. also need new gasket.

Question - Where to get the gasket and and fitting. (I temporarily manged to fit it with what was left of the thread


There is also a leak of fuel from the carburettor not sure what to do with this other than take it off and clean it.

And lastly, the engine ran for 15 minutes, then the tell tale water started to dry up so I switched it off. Any ideas on this?

 

[Tremlett 15]

This is way too geeky. Better stop now

agree........just hope RIN gets his o/b running ok, its great to have these old engines all running, my Merc 500 which we bought new in 1976 is still as original, running on original prop & spark plugs....!!!

 

[jfm]

jfm, was it not a few years later that the hp rating changed, I dont know the year but my 500 50hp became "45hp classic" model, was not closer to 1986/88 ????

It might have been different years for different models. I do remeber the 4cyl 50 becoming 45 classic, and I can't remember when that was.

I'm as certain as can be that 81 was the change over date for the 6-inlines. My father and I got a brand new 90 tower of power in Jan 1991 and I was very fussy with the dealer to make sure it was a 115 @flywheel. I checked the carb jet sizes before accepting delivery, and the dealer was on my side to make sure I got a "115". I collected that engine from the dealer 27/1/81 (it was my birthday!)

It was an utterly stunning machine. I still remember it on its stand gleaming brand new in the garage, almost 6 foot high, and the sound of the thing at 4500rpm+ is wonderful - still the best outboard sound ever. We kept it (in Ireland, West Cork) 20 years and I stupidly sold it in 2001 and bought a new boat with a 4 cyl 125 Merc, which does the job but is a boring old piece of junk in comparison. I so wish I hadn't sold it; I'd have had it fully restored and rebuilt, and kept it just for fun, if I had the money then that I have now. Ho hum. If anyone ever sees it for sale (the bloke who bought it took it to Cornwall) let me know - serial #5777855

 

[jfm]

You may well be right there. It was sold to us as reconditioned but I suspect the only reconditioned bit was the case. Here is pic I took this morning.
Anyway, I cleaned out the telltale pipe and got this which I was pleased with
The problem being that I broke the fitting that secures the pipe to the engine block. This has a thread that fits on to a housing above the engine blok. You can see the hole it comes from under the spring in this pic. also need new gasket.
Question - Where to get the gasket and and fitting. (I temporarily manged to fit it with what was left of the thread


There is also a leak of fuel from the carburettor not sure what to do with this other than take it off and clean it.

And lastly, the engine ran for 15 minutes, then the tell tale water started to dry up so I switched it off. Any ideas on this?

RIN, I reckon VicS is right and it's a 1979. Those decals look after market to me, not original mercury. The detail isn't right, and loads of aftermarket "make it look newer" decals have been avaialbe for mercs over the years

Spares are sometimes available. - mostly from US via lots of websites. Otherwise a component like that can be made - thread will be imperial, UNF probably

There are lots of possbilities for leaky carb. New gasket can be made by copying the old one. It could be overfilling the bowl if the float valve is faulty (might need a clean only)

I like your ladders set up! I have no idea why your wife wanted you to get rid of it

 

[Tremlett 15]

It might have been different years for different models. I do remeber the 4cyl 50 becoming 45 classic, and I can't remember when that was.

I'm as certain as can be that 81 was the change over date for the 6-inlines. My father and I got a brand new 90 tower of power in Jan 1991 and I was very fussy with the dealer to make sure it was a 115 @flywheel. I checked the carb jet sizes before accepting delivery, and the dealer was on my side to make sure I got a "115". I collected that engine from the dealer 27/1/81 (it was my birthday!)

It was an utterly stunning machine. I still remember it on its stand gleaming brand new in the garage, almost 6 foot high, and the sound of the thing at 4500rpm+ is wonderful - still the best outboard sound ever. We kept it (in Ireland, West Cork) 20 years and I stupidly sold it in 2001 and bought a new boat with a 4 cyl 125 Merc, which does the job but is a boring old piece of junk in comparison. I so wish I hadn't sold it; I'd have had it fully restored and rebuilt, and kept it just for fun, if I had the money then that I have now. Ho hum. If anyone ever sees it for sale (the bloke who bought it took it to Cornwall) let me know - serial #5777855

what boat did you run the "tower" on ?

yes, that serial No is USA 1981. ( 1980 & 1981 Merc 90 had the same model year )

 

[RIN]

Oooops - The fact that the telltale stopped gushing after 15 minutes may be explained by the fact that there is a leak in the dustbin and the water level had dropped below the top of the lower unit. Presumably that is where the water intake is?

 

[jfm]

Oooops - The fact that the telltale stopped gushing after 15 minutes may be explained by the fact that there is a leak in the dustbin and the water level had dropped below the top of the lower unit. Presumably that is where the water intake is?

Yes! The water is sucked in thru a vertical line of holes both sides of the gearbox unit, just below the cavitation plate, above the "bulb" inside which the F-R gears are located. Beware running it much without water cos the water pump needs water to lubricate it. You'll be ok if you ran it 30secs or so cos it will still have been wet

 

[VicS]

jfm, was it not a few years later that the hp rating changed, I dont know the year but my 500 50hp became "45hp classic" model, was not closer to 1986/88 ????

The method of rating from the crankshaft power to the prop shaft is covered by ICOMIA 28/83 SeeHERE
however I think some manufacturers were quoting prop shaft rating before that while others took some time after to bring the model descriptions in line with it. They usually quoted the actual power according to ICOMIA 28/83 in the detailed spec though

 

[volvopaul]

What an interesting post, so many merc fans on here, I used to lust after them in my youth.

 

[[2068]]

In the early 80's, we used to launch an inflatable from the beach at Herne Bay or Whitstable with a Chrysler 15hp on the back.

It was fun as a teenager, but I always lusted after the speedboats that were hammering around further out to sea, in garish colours, and invariably powered by huge black Mercury two stroke outboards. The straight sixes sounded the best - it still makes my hair stand up on end if I hear one.

I do own a merc.

5hp.

Single cylinder

 

[Tremlett 15]

I do own a merc.

5hp.

Single cylinder

what ever you do, dont ask us to find what year it is............

 

[jfm]

Ref your Q earlier Tremlett, I had the "tower" on a 17 foot day boat, using the much-cloned 17 foot hull used by Mariner/Nab/Pilot/Wilson Flyer. Mine had the proper internal moulding so it was foam filled proper job. I had it custom moulded (2 of them actually) by Midland Mouldings (Geoff Lusty) who later morphed into Minster Composite Industries. Based in Nottingham. They were contract moulders for many of the big names and made all the Relcraft hulls in the 1980s, for example