L6 250/292 ?

[starsnstripers]

the merc manual specs say that the 250 L6 was 160hp with a 1brl carb. then it says the 250 was 165hp with a 2brl carb. I just picked up a 292 and the manual says the 292 was 200hp. Now, is that with a 1brl,2brl or 4brl carb? It doesn't specify that so i'm curious what it would be with my 2brl carb? anyone? thanks

 

[Don S]

Re: L6 250/292 ?

What year engine, What manual, and what use is that number?

 

[starsnstripers]

Re: L6 250/292 ?

1969 and that manual thats a 1gb download. What use is what number?

 

[starsnstripers]

Re: L6 250/292 ?

292ci 6cyl. Bore=3.87 Stroke=4.12

 

[Don S]

Re: L6 250/292 ?

The 200 was a 1969 model and only used that year. It had a Qjet carb.
The HP rating is the "Number" , and don't even think of trying to compare it to todays engines.
Somewhere along the line, and I don't remember when it was, the HP rating went from engine to propshaft hp.
In 69, the HP rating was crankshaft hp, not propshaft.

 

[achris]

Re: L6 250/292 ?

sns,

Merc used the 292 for just 1 year, 1969. One has to ask oneself why it only lasted 1 year???? It was rated at 200hp, with a 4 bbl Quadra-junk on it....

Hope this helps you make the right choice....

Cheers,

Chris...... (for course)

Edit - Seconds Don, seconds!!

 

[starsnstripers]

Re: L6 250/292 ?

Got it Don, I want to compare apples to apples so i'm talking about flywheel hp which is probably what the manual means back in 69. If i understand something is that a longer stroke engine has more low end torque and a higher compression ratio? So if merc said it was 200hp with a 4brl carb it should be like 190-195hp with a 2 brl carb? is that a close assumption?

 

[ziggy]

Re: L6 250/292 ?

The 200 was a 1969 model and only used that year.

Merc used the 292 for just 1 year, 1969. One has to ask oneself why it only lasted 1 year????

does anyone know the answer to achris's question...... why was it only used for one year?

 

[achris]

Re: L6 250/292 ?

Got it Don, I want to compare apples to apples so i'm talking about flywheel hp which is probably what the manual means back in 69. If i understand something is that a longer stroke engine has more low end torque and a higher compression ratio? So if merc said it was 200hp with a 4brl carb it should be like 190-195hp with a 2 brl carb? is that a close assumption?

Not really. As well as compression ratio, there is air flow to think about. The 2bbl carbs are good for about 250cfm (max). That Quadrajunk is good to about 600cfm. Do the sums on the engine and find out how much air it would require at full noise. If it's greater than the flow the carb can deliver, then you need a bigger carb... simple.

292 cid = 0.1689815 cubic feet. Turning at 5000revs will require 0.1689815 x 5000 x0.5 cubic feet per minute. = 422.45375 cubic feet per minute.... = throw away the 2bbl. Even at 4000revs it would need 337 cubic feet per minute.

Chris.............

 

[achris]

Re: L6 250/292 ?

does anyone know the answer to achris's question...... why was it only used for one year?

Even by 1969 standards it was a fuel guzzler. You needed to own an oil company to keep it running!!!

 

[Lakester]

Re: L6 250/292 ?

hello,

what was the merc option for 200HP in 1970? may offer a clue, other than just perhaps due to addl weight.

regards
lakester

 

[Don S]

Re: L6 250/292 ?

does anyone know the answer to achris's question...... why was it only used for one year?

It was almost 40 years ago Ziggy, no doubt it didn't work that well in a boat. Even Mercruiser was just 5 years old at that time.

Those were the trial and error days .............. Mostly error

 

[ziggy]

Re: L6 250/292 ?

thankyou....... that why question just seemed like it might be relevent for sns...... i always wondered why too.......

 

[starsnstripers]

Re: L6 250/292 ?

Stop picking on my Stovebolts! There are some nice L6s out there still running with less issues than alot of the new junks! haha! There's a mercruiser L6 292 on ebay right now that has a holley 4brl for 900.00 but it's about 700 miles away. Atleast this 292 has the mounting ear/tab to recieve the merc front eng. mount,unlike the 250 i have. Thats a plus! Well I don't know I'm going to run the 250 this coming season anyway and prob rebuild the 292 for next yr. It will be fun to try and see the difference, who knows i might go back to a 250 or do up the 292 for the SS 235 i'm looking at with the outdated obsolete OMC - V8 in it. Thanks for the input and i got my answer: 200hp w/4brl carb.

 

[starsnstripers]

Re: L6 250/292 ?

I believe the L6 is happy running at about 4300 rpms. and how do you figure out compression ratio?

 

[achris]

Re: L6 250/292 ?

I believe the L6 is happy running at about 4300 rpms. and how do you figure out compression ratio?

(Swept volume + combustion chamber volume) / combustion chamber volume.

....that has a holley 4brl....

RUN AWAY! FIRE HAZARD, RUN AWAY!!!

Chris............

 

[starsnstripers]

Re: L6 250/292 ?

HAHA ! Achris so the holley is a fire hazard and the other is a quadrajunk ! Any suggestions for a good 4brl for the L6 292? And dont say get a 4.3! it;s not in my budget!!!

 

[achris]

Re: L6 250/292 ?

HAHA ! Achris so the holley is a fire hazard and the other is a quadrajunk ! Any suggestions for a good 4brl for the L6 292? And dont say get a 4.3! it;s not in my budget!!!

Personally, a Carter/Weber AFB. If I had to choose between the fire hazard and the 'junk, it would be the 'junk. They are a PITA to set up, but once they're done right they're usually ok. Whatever you get, make sure it's a marine carb. Yes, there really is a difference!

Chris.........

 

[starsnstripers]

Re: L6 250/292 ?

WIKIPEDIA SAYS IT'S FUEL EFFICIANT! longer stroke than bore, higher compression ratio less overheating than the 250. We're gonna find out GPH I'll guess about 2.5 at 2800 rpm maybe 3. Whats your calculated guess?

 

[starsnstripers]

Re: L6 250/292 ?

Whats your 4.3 get for GPH at 2800? curious?