starsnstripers, I-6 questions, quadrajet on Merc 250ci?

[system-f]

Do you have pictures of the mount you built for the starboard side engine mount that was missing on one of your blocks?

Did you ever get the 292 in? I would love to see some pictures of the elusive Merc 200hp I-6 292.

I did look at your old posts and tried tons of searches but couldn't find anything.


Last question, does anyone have a 4bbl carb on their Merc 250CI I-6? My manifold looks to accept one (quadrajet?)

 

[ziggy]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I would love to see some pictures of the elusive Merc 200hp I-6 292.

that would be the one that's bolted up to a mercruiser II drive. not many of them around that i've seen.

Last question, does anyone have a 4bbl carb on their Merc 250CI I-6? My manifold looks to accept one (quadrajet?)

mine too, but i think any 4bbl on a 250 I6 engine is more carb than it can handle... there's nothing to be gained from the conversion from what i've read on it... don't yer 2gc work ok?

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

mine too, but i think any 4bbl on a 250 I6 engine is more carb than it can handle... there's nothing to be gained from the conversion from what i've read on it... don't yer 2gc work ok?

2gc works great after rebuild, before that accel. pump wasn't working. I was told 400cfm is max for the 250, but this is from a bunch of guys who want to go fast. I thought if a 4bbl was offered factory on the 250 I-6 it might be worth looking into, if it wasn't offered factory I would be better to save my money. Then again, what it really comes down to is creating more work for myself while I have downtime at work.

Does anyone have the picture of that mount made to replace the starboard side ear that doesn't come on some 250s? My block is cracked and although it works fine I need to have a backup plan.

 

[ziggy]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I thought if a 4bbl was offered factory on the 250 I-6 it might be worth looking into, if it wasn't offered factory I would be better to save my money.

i don't think it was offered. least i've never seen any application regarding it. yep, best to save your bread.
me personally, i've resigned myself to my chevy 250 L6 is what it is in the marine version. the only thing ya can do is keep her running in tip top shape. which in my case, is enough of a challenge to keep me busy....
don't get me wrong though, i like my 165hp just fine. really fine even. it's a great engine for marine use. it just don't have any gofast mods available for it.

sns will have to post up his pics on the mount tab if he has one. i believe he was successful with that mod to his block...

 

[Bt Doctur]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Had Edelbrock 4bbl on mine , worked very nicely. The last one i made for the 292 IL6 was from 4 x4 x 3/8ths thick aluminum angle. Attaches to available casting holes and fits nicely.

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Did you notice a significant power increase? Fuel consumption?


My 6 does pretty darn good, tons of torque and yanks skiers out of the water with little effort. Not to mention the straight 6 is one of the fastest starting motors and I do not know why. Even when I had a blown head gasket and 0 compression on 4 and 5 the thing would start with one crank when cold. I was thinking of dumping a 350 in her but after pulling the plugs I am going to keep the 6.

 

[jerryjerry05]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Mercruiser made the I-6 with both 2 and 4 bbl carbs.Mid 70's. It came with a real trick looking breather. All the years I worked on boats I've only ran across 2.J

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I'm bringing this back up rather than creating a new post. My manifold will accept a 4bbl SOMETHING. Is the bolt pattern square bore or spread bore? I would really like to run a marine quadrajet as it may be more effecient if I stay out of the secondaries (how many people have told themselves that). I am told I can get more acceleration from a quadrajet as the primaries are smaller than my 2bbl and the secondaries won't open until they are needed (mechanical carb with secondary airvavle control).

pic of manifold bolt pattern:

 

[Bondo]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I am told I can get more acceleration from a quadrajet as the primaries are smaller than my 2bbl and the secondaries won't open until they are needed (mechanical carb with secondary airvavle control).

Ayuh,... The 600cfm Merc/ Weber/ Edlebrock Performer/ AFB carbs are the Same Way....
Tiny primaries,+ pretty Big secondaries...

It's the same carb Merc went to when the Quad-jets drifted off into history...

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I love having more options, thanks again Bond-o!

 

[ziggy]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

i'm still of the impression that there is no reasonable options to increase hp or a 250 L6 engine. if there would have been, mercuriser probably woulda done something different, anything they tried only lasted a moment. think 200hp L6. but since it's your dime give it a go. i do hope ya'll let us know how it works out for ya.. fuel consumption, speed, hole shot.. there's a lot of folks that will be interested in your findings since most folks always want more hp..

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

The core question still hasn't been answered. Is my manifold a spread bore or a square bore? If I have to use a square bore to spread bore adapter that could possibly negate any enahncement the quadrajet would give me. I am worth giving it a shot, but chances are it won't do anything if much. I think the quadrajet is more tuneable than my 2g carb. Also a divorced choke quadrajet rebuilt is cheaper than my 2bbl rochester with no core.

 

[Lou C]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

I can't answer that question but as far as whether a 250 could handle a 4 bbl..well many 4.3s...which are 262 cu in only 12 cu in larger have had them (mine does and it works great....nice surge of power over 3000 rpm)....so I don't see why not....I like inline 6s having had one in my old Jeep for years...perfect primary and secondary balance and very easy to work on....just on the long side in a smaller boat....

 

[Fishermark]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Do you have pictures of the mount you built for the starboard side engine mount that was missing on one of your blocks?

Well, I'm not Starsnstripers.... ... but here's what I did recently:

A couple of thick bars of aluminum, a liberal coat of JB Weld, and drill and tap a few extra screws.

 

[windsors03cobra]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

The 250ci manifold accept a spreadbore, I think 90% of spreadbores are quadrasewers and are Rochester Products.

Ford used Holley/Autolite square bore which has all the same size venturi's hence the square name.
Dodge used Carter carbs and all but the thermobog were square bore with a somewhat modified but compatible with Holley's square bore.

When I put the motor in my boat I just unbolted the carb adaptor from the manifold instead of unbolting the carb from the adapter well MerCruiser couldnt get the gasket so I went to the auto part store and got a Mr Gasket quadrajunk gasket, perfect fit.

Fishermark: Sweet work on that elusive front mount, more than one way to skin a cat I guess. I thought I would never find an engine like that when I was looking I felt so so lucky when the first supposable "good runner" i was looking at for $100 had it, I was sold.
Damn motor never missed a beat this summer and made us all real happy.

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Awesome work. What did you do to figure out the alignment of the two holes? Just bolt up the front mount to the other side and mark them?

The 250ci manifold accept a spreadbore

Confirmed tonight. My quadrajet gasket fits on my manifold perfectly once the 2bbl adapter is removed.

 

[Fishermark]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

What did you do to figure out the alignment of the two holes? Just bolt up the front mount to the other side and mark them?

That's exactly what I did. There is a tab on the bottom of the front mount that helps line everything up pretty easily. I had the blank aluminum bars laying around which is why I used them.

By the way, adding the extra holes is pretty easy on the block there. It drills and taps with no problem.

 

[Bondo]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Ayuh,.... That's a pretty Sweet piece of Drillpress Engineering there Mark,.... Great Job...

 

[Fishermark]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Why thanks! Ah - necessity.... the mother of invention.

 

[system-f]

Re: starsnstripers, I-6 questions, quadrajet on Merc 250ci?

Thanks mark, that sure does open up many more doors for me as far as blocks go and I can get free scrap aluminum or 304 stainless at work.