Merc V6 History

[powerabout]

What year was tbe first looper inline?

[Capt.Insane-o]

1988

[rckid74]

What year was tbe first looper inline?

The 880 (4cyl) came out in1985 but the 879 (3cyl) came out a year or two before that. --- Sorry Captain!!

[Dave S]

They are tuff motors.......Just keep the carbs clean.... and they will out last 3 lowers.........

[Dave S]

The early ones.... had a habit of pulling the sleeve into the crank. When piston taper got big.... not good.

[Dave S]

Rckid 74..... were you behind the L4 66 cid motors adjst on the exhust port to make it think....pulse tunning/ also the 2/4 gousse neck... into a 3 cly mid? I ask because you did the V4... 60 and tried to fool it......120/0 ......2 bang....

[rckid74]

Rckid 74..... were you behind the L4 66 cid motors adjst on the exhust port to make it think....pulse tunning/ also the 2/4 gousse neck... into a 3 cly mid? I ask because you did the V4... 60 and tried to fool it......120/0 ......2 bang....

I never did a 66 cid engine. The V4 I tried was 81 cubes.

[rckid74]

Ouch!! You hit a nerve with that one Bernie. I was hoping I would'nt have to say anything about the 880. Not one of my better efforts!

Summer of '76 and the V6 (175HP) was looking like a winner so the powers-that-be decided they'd like to extend loop scavinging into the lower power ranges. I guess it seemed natural to just take 2 cylinders off the V6 and make a V4 to serve the 100 - 130 HP range. The V6 already had a 150HP version on the boards. So I was pulled off the V6 and assigned the V4 project. Well 2/3's of 122 = 81.33 cubic inches which (without pulse tuning to help) is kinda skimpy to ask for 130HP. But I tried. I really tried. It was to be a 60 degree V4 using the same machining and assembly lines as the V6. Makes sense. But 130 just wouldn't come. I tried several firing orders, I tried different exhaust arrangements. I even tried a wild idea I had of firing the engine as a three cylinder (#1 cyl fires, 120 later #2 cyl fires, 120 later both #3 and #4 fire together) so I could use pulse tuning, and this was the most powerful version I came up with (I think about 125HP). But the balance was not very good and the double pulse would put a lot of extra load on the gear set, so we decided against that. I wasn't getting anywhere so somebody up there decided to scrap the v4 idea and instead go for an inline 4 and a matching inline 3. That way we could cover the entire midrange (60 to 115) with new loopers. Yes they lowered the top expectation and decided to also make a 135HP V6 to cover the upper midrange. That's how the 880 (big inline 4) project came about. Getting late - I'll talk a little about the 880 tomarrow.

This thread is supposed to be about the V6 so maybe the administrators will not be too happy about me expounding on the inline 4 looper here. I'll try it anyhow.

The story about the big I4 is not so much about the design and development of the engine ( that was pretty much straight forward) as it is about how it got that 2-by-4 moniker.

After going thru a couple of different exhaust systems, the one we ended up with gave us an honest 115 HP, and everything looked good till we got it on a boat and started exploring the entire throttle range. All was nice and smooth till you came down to about 2300 RPM and then it got really ratty and stayed that way on down to idle. I just thought it was a carburation problem at first so we set our carb expert to work on it. Time went by and he got it a little better but still no where near good enough for production. In the meantime production dies and tooling were being made, we were gearing up for a quick introduction but the dam thing would just not idle or off-idle. Even Jordan was on my back to get the line started. So I, along with several others, was down on the river one day trying to come up with something when (as I was adjusting the low speed needles), all of a sudden the engine broke into the nicest idle you ever want to see. Sat there just pug-pug-pugging away. I thought wow!! What happened. I called over John Litgen to show him. He was amazed too but after awhile he says, "I think its idling on just two cylinders". So we started pulling plug wires and sure enough cyls 1&2 were dead. I had leaned out those two cyls to the point they quit but 3 & 4 were still good. Man was I disappointed. ---- But after awhile I got to thinking why not try to promote that and see what happens. So I idle out of the slip - punch it and blaaa - nothing. Those two cyls would just not light up. It was obvious -- they had leaned out and dried up the crankcase to the point where there wasn't enough fuel in there to act as a acceleration pump. OK -- so lets just add an acceleration pump to those two cyls - actuate it by the throttle linkage - and we're all set. And that's what happened. We made it into production - a little late - but I could stop sweating. And that's how the 2 by 4 came about. 2 cylinders at idle and off idle -- 4 cylinders everywhere else.

I guess it went over fairly well. I didn't hear a lot about it from the field except that the commercial fishermen really liked it because they do a lot of idling around while working their nets and this engine was super efficient at idle. Just sipped fuel.

[FMP]

Thread up man

[rckid74]

Thread up man

But I'm answering a question posed to me in this thread!!

[FMP]

I'm going to do something boring like start the thread with a bunch of patent diagrams etc later on if I'm not sleeping. I like the motor and it would be an interesting thread.

[rckid74]

I'm going to do something boring like start the thread with a bunch of patent diagrams etc later on if I'm not sleeping. I like the motor and it would be an interesting thread.

OK --- Go!!

[JFL]

True story, I remember it well

[Dave S]

I was called by a guy with one.....used.... it had a rattle.....at top end. Sounded like a 2cly motor bike......Ringadinnng....Drove me crazy.......Some one had stacked the main jets......upside down. And any thing Merc history you can post is welcomed.

[FUJIMO]

This thread is supposed to about the V6 so maybe the administrators will not be too happy about me expounding on the inline 4 looper here. I'll try it anyhow.

The story about the big I4 is not so much about the design and development of the engine ( that was pretty much straight forward) as it is about how it got that 2-by-4 moniker. ---- After going thru a couple of different exhaust systems, the one we ended up with gave us an honest 115 HP, and everything looked good till we got it on a boat and started exploring the entire throttle range. All was nice and smooth till you came down to about 2300 RPM and then it got really ratty and stayed that way on down to idle. I just thought it was a carburation problem at first so we set our carb expert to work on it. Time went by and he got it a little better but still no where good enough for production. In the meantime production dies and tooling were being made, we were gearing up for a quick introduction but the dam thing would just not idle or off-idle. Even Jordan was on my back to get the line started. So I, along with several others, was down on the river one day trying to come up with something when (as I was adjusting the low speed needles), all of a sudden the engine broke into the nicest idle you ever want to see. Sat there just pug-pug-pugging away. I thought wow!! What happened. I called over John Litgen to show him. He was amazed too but after awhile he says, "I think its idleing on just two cylinders". So we started pulling plug wires and sure enough cyls 1&2 were dead. Man was I disappointed. ---- But after awhile I got to thinking why not try to promote that and see what happens. So I idle out of the slip - punch it and blaaa - nothing. Those two cyls would just not light up. It was obvious -- they had leaned out and dried up the crankcase to the point where there wasn't enough fuel in there to act as a acceleration pump. OK -- so lets just add an acceleration pump to those two cyls - actuate it by the throttle linkage - and we're all set. And that's what happened. We made it into production - a little late - but I could stop sweating. And that's how the 2 by 4 came about. 2 cylinders at idle and off idle -- 4 cylinders everywhere else.

I guess it went over fairly well. I didn't hear a lot about it from the field except that the commercial fishermen really liked it because they do a lot of idleing around while working their nets and this engine was super efficient at idle. Just sipped fuel.

...One of those "Hey, you got chocolate in my peanutbutter moments"... Great story & very interesting Mercury history we all love hearing Jerry. Keep 'um coming.