Mercury "Flat-Top 800"

[raymar]

Do any of you old-timers know anything about what was known as the
"Flat-Top 800" engines that were produced & sold about 1960? A local mechanic that worked for the Merc dealer had one on a wooden Switzer Shooting Star that he ran. I remember the boat/motor setup but I don't know anything about the engine specs.etc. I spoke with the mechanic last week and all he could tell me that it was called a "Flat-Top 800" made by Merc and not a Quincy modified engine.
The mechanic is in his 80s and still working locally on boats & motors. Some of you real "old-timers" may be able to shed some light on this subject.
:confused: :confused:

[Mark75H]

1960 76ci, the second 6 to use the more modern "flat top" cowl. The first was the 1959 Mark78 66ci 70 hp

The second generation of the 76ci motors used an improved combustion chamber and were 85hp

The 76ci motor is kind of an orphan in the Merc family, the same stroke as the 60 & 66 ci motors, but a longer crank in a longer block with bigger bores; no 2 cylinder or 4 cylinder motors using the same bore. It was replaced with the 89ci block for the new 85 and 100 hp Mercs.

The 800's were the last Direct Reversing (Dockbuster) Mercs and the first full gear shift Mercs in 1961. I think the 800's were also the first Mercs to use thru prop exhaust. My old reference book says they weighed just under 200 pounds and cost just under $1000, a lot of money back when the minimum wage was $1 an hour and a lot of people brought home less than $30 a week after taxes (3 years take home pay to buy a big Merc without the boat or trailer)

[Bruster]

My old reference book says they weighed just under 200 pounds and cost just under $1000, a lot of money back when the minimum wage was $1 an hour and a lot of people brought home less than $30 a week after taxes (3 years take home pay to buy a big Merc without the boat or trailer)

3 Years? :eek: Were you a loan shark back then?:cool:

[Mark75H]

Ooops ... I slipped between months and weeks didn't I?

33 weeks of take home pay, not months, so it would be a little over 8 months of every penny for a non excutive type's pay

[wogi]

I do have a gear case off a 1961 800 Merc inline six This would be the first full gear shift type and it has exhaust threw the prop hub and has the water pickup in the trim tab. Its a short shaft also. It is in real nice shape, used in fresh water. I did take the cover nut off, and all the interals look to be in great shape. This case has been sitting around for as long as I can remember. So if any one needs it for a project ,get ahold of me:D

[raymar]

Thanks Mark 75H; Now I know what he was talking about. I was aware of the two different 76 c.i.engines but I didn't know the "Flat-Top" meant the cowl top. I thought it may have meant something else.:)

[lloyd]

Thanks Mark 75H; Now I know what he was talking about. I was aware of the two different 76 c.i.engines but I didn't know the "Flat-Top" meant the cowl top. I thought it may have meant something else.:)
As I rember it, I was there, it ment the shape of the combuston chamber, The 800 would run circles around 850 if you didn't use good gas and oil they'ed burn a piston merc chaned to there hemi style to hold togeator less compresion some old 800's would clean 1000's Lloyd Burns Lloyd's Marine.ps.Charged $85 to get new 850 long block, most owner;s didn't like the loss of performace.

[Mark75H]

I'd like to see both types to confirm this. Maybe DaveS and LarryR could show us ... since both of them are 76ci guys

[raymar]

LLoyd I was glad to hear from you on the subject. I remember several 800 blocks around here were replaced with the 850 blocks but I never knew why at the time.
A good friend put a Merc 1000 on a boat he had lost an 800 off of jumping towboat wakes in the Ohio and he always swore the 1000 was 4-5 mph slower than the 800. This was back when the 1000 Mercs just came out.
:D

[J Taylor]

For us wankers who love to use Tillotson KC carbs from bigger Mercs on our Mer 40 and 44 cube Modified gas racing engines those KC6s from Merc 800 6 bangers turned out to be pretty remarkable! Grab them any time some turn up. Some use them with their fixed screw in high speed jets where others like me who like to turn in them adjustable high speed needles to get rpms found those KC6s make both the Merc 55H (40 cube) and Merc 44s where they pull like crazy throughout the rpm ranges where the larger KC1s and KC2s carbs just don't do that as well.

Those direct charge Merc type pistons seemed to love burning up real easy in the 3 banger 650s too. Seems anytime I hear about a Merc 850 4 banger direct charged engine being used in racing you also hear they scorch pistons too but not as frequently as the 3 holer Merc and Mariners did. :)

[SUPAJAY]

So the 800 was underrated ?

[150aintenuff]

what merc back in the day wasnt.... merc 400 was 45 hp... and that block became 50 hp in 1963 and was that way till the late 80's where it was detuned a bit back to 45 hp and then 40 hp... even propshaft rated they made the 45-50hp from the same 4 banger block... interesting aint it..

[Mark75H]

So the 800 was underrated ?

esp if it had the late run "Powerdome" combustion chamber vs the early centered spark plug combustion chamber