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View Full Version : OMC 1 3/8" carbs



andmar
01-11-2017, 06:23 PM
Anyone know what year/hp cross flows used 1 3/8" carbs.

Thanks

brichter
02-01-2017, 08:45 PM
Those are V6 carbs and some 140 v4s......Do you need some?

andmar
02-02-2017, 05:33 AM
I picked up a set on ebay, but thanks.

Xpress2830
03-07-2017, 08:53 AM
Good mornin hows it goin? I saw your post here. The carbs you are referring to are these 1 3/8 venturi are carb bore? I have some 50 twin carbs rhey are 1 1/4 venturi and 1 / 1/2 bore. If these are in fact 1 3/8 venturi I am interested in locating some. Thanks, Bobby

filthy phill
03-07-2017, 09:38 AM
the carbs talked about here are twin barrel carbs, no way to fit them on a twin cylinder motor.
they are for the v4 motors and have just the two bodies, 1 up top and 1 down the bottom.

LittleCharger
03-07-2017, 10:09 AM
the carbs talked about here are twin barrel carbs, no way to fit them on a twin cylinder motor.
they are for the v4 motors and have just the two bodies, 1 up top and 1 down the bottom.

You can run them on a twin, just need to make your own intake out of aluminum, the reeds in a twin are the same as the v4 reeds

The issue is you'll won't get the performance your looking for unless you port it for all the fuel and once ported for all that fuel it will be only happy on the top end.

you can look to some mercury 125 carb for a bigger single bore

filthy phill
03-08-2017, 04:34 AM
No that's not really true now is it. When people use the twin barrel carbs for one cylinder they do not use v4 or v6 carbs. They use totally different carbs like those on the old 3 cylinder racing motors. V4 carbs and three twin carbs for the 3 cylinder look similar at a glance and that's it.
Go look on the mod 50 secrets and you can read about the twi carbs. But even they are not as good as the larger 56 carbs.

Hevi Kevi
03-08-2017, 10:52 AM
No that's not really true now is it. When people use the twin barrel carbs for one cylinder they do not use v4 or v6 carbs. They use totally different carbs like those on the old 3 cylinder racing motors. V4 carbs and three twin carbs for the 3 cylinder look similar at a glance and that's it.
Go look on the mod 50 secrets and you can read about the twi carbs. But even they are not as good as the larger 56 carbs.

http://www.boatracingfacts.com/forums/showthread.php?17108-56er-six-pack-build/page2 Doesn't sound like a totally different carb to me. Solder over holes on the butterfly and change or modify main nozzle...

filthy phill
03-08-2017, 12:42 PM
there ya go, you cant put them on without a lot of modifications, and even then you have start the motor revving it brains out,,IF you manage to start it.
the v4 carbs are not ever going to work good on a 2 cylinder omc motor. ever tried getting the main nozzles out of a v4 carb ? and then fitting a nozzle of the wrong size and type.
you could fit the twin barrel 3 cylinder carbs and just jet them .

lots of differences and plenty of people have tried them and come unstuck, not worth the effort... by the time they work you would of changed everything.

like saying a 13 inch tyre fits a 15 inch rim, you only have the change the wheel .

Hevi Kevi
03-08-2017, 01:37 PM
there ya go, you cant put them on without a lot of modifications, and even then you have start the motor revving it brains out,,IF you manage to start it.
the v4 carbs are not ever going to work good on a 2 cylinder omc motor. ever tried getting the main nozzles out of a v4 carb ? and then fitting a nozzle of the wrong size and type.
you could fit the twin barrel 3 cylinder carbs and just jet them .

lots of differences and plenty of people have tried them and come unstuck, not worth the effort... by the time they work you would of changed everything.

like saying a 13 inch tyre fits a 15 inch rim, you only have the change the wheel .

Well, if anyone knows, I'm sure it's you.

filthy phill
03-08-2017, 02:21 PM
why do you have to keep trying to make a problem ?

a fella asked a question and got a wrong answer, now your just trying to prove along with the other Canadian that they can work on a twin.
well anything can work if you want to go to extremes.
to just get them and make a plate to hold them wont work, they need modifying in a lot of ways to work, is that so hard to understand ?

LittleCharger
03-08-2017, 05:48 PM
61651We'll be sure to tell Anthony that his Old FEH two cylinder with the exact stock carbs in question doesn't work. She's a pain to get on plane but it's a clock start.

Sure progressive carbs would work better just for the bottom end but they are a little tougher to come by for the average Joe. V4 carbs off an 85 actually work pretty good as they have a 1" Venturi which is the same as the primary in the progressive carbs. Sometimes the two barrel 85 will work better then a larger single carbs simply due to the vacuum you don't know til you try it.

To put progressive carbs on a 2 banger takes the same modifications for linkage and mounting etc. as the v4 carbs as an intake was never designed by omc to take any two barrels unlike the mod50.

At the end of the day you select carbs based on your application, if your gonna go mod sometimes your gonna have to give up one end to gain on the other.

You should try some Chrysler carbs

Hevi Kevi
03-08-2017, 06:54 PM
why do you have to keep trying to make a problem ?

a fella asked a question and got a wrong answer, now your just trying to prove along with the other Canadian that they can work on a twin.
well anything can work if you want to go to extremes.
to just get them and make a plate to hold them wont work, they need modifying in a lot of ways to work, is that so hard to understand ?

Phill,
The fella looking for carbs for his twin may or may not have been asking about adapting v4 or v6 carbs to his motor. You told him there was no way it could be done. LC told you otherwise. You do realize this is a racing site and some people here don't mind modifying things to make them work right? Someone sent me a link to a thread on E-nation the other day that you joined just to tell them how stupid they were. You enjoy pointing out what you think are errors all the time. Most of the time it's just because you don't understand. Reasons like this is why I make some of the comments I do to you. I see you edited your post from the original that was emailed to me. You told me not to reply because I can tell you in person very soon. Are you planning a trip to Canada Phill?

Xpress2830
07-10-2017, 08:08 AM
Hey Phil I have some OMC50 Twin mod questions

filthy phill
07-10-2017, 11:25 AM
Might be best to ask those who race the twins. Lots of people around with them.

MODIFIEDOUTBOARD
07-24-2017, 10:38 PM
The 1" venturi 2bbls will light up a stock OMC 50 Twin.
Getting on plane isn't that bad with a light boat.
Only thing I never did was rig a PROGGRESIVE throttle to open one barrel at a time.
There are several sound reasons that 2bbls work on a twin........

MODIFIEDOUTBOARD
07-25-2017, 08:23 AM
Hey Phil I have some OMC50 Twin mod questions

go to https://www.youtube.com/watch?v=gnqr7C2jcuY

One of my modified 45ss Engines on mini deep vee in Saint Thomas............
Best Pass of Day was 61mph @ 6,000 rpm w/12p Dewald tunnel boat prop buried deep under boat.

filthy phill
07-25-2017, 09:48 AM
its amazing sometimes how fast little mini boats look when doing around the 45 to 50mph speed.
anything over 40 in a mini boat is pretty fast though.

what is the length of that ? 11ft

sharpeye Mike
07-26-2017, 04:00 PM
That boat is not doing 45-50 filthy, I'm sure it's doing what modified said. No small race boat in your area that you can buy filthy? Trust me when I say big difference in what you play with and I guaranty you WILL fall in love with it.

filthy phill
07-26-2017, 05:30 PM
too much smoking the green stuff.

but if it keeps you happy then carry on, it dont hurt anyone.

LittleCharger
07-27-2017, 03:57 AM
too much smoking the green stuff.

but if it keeps you happy then carry on, it dont hurt anyone.

We run into the 60's no problem with our two cylinder and we are set up to circle race, limited to sst45 specs for porting and run less compression then a spec sst45 motor. Lots left on the table to go faster in a straight line

MODIFIEDOUTBOARD
07-27-2017, 04:12 AM
We run into the 60's no problem with our two cylinder and we are set up to circle race, limited to sst45 specs for porting and run less compression then a spec sst45 motor. Lots left on the table to go faster in a straight line

I just thought Osa is really brave to take that thing out in open waters and hop over waves with it. He was undefeated in that little boat.

Ya if Osa went up with the set up and allow the 12p Tunnel Boat prop surface it would have been a lot faster.
He is draggin the gear case thru water and not allowing prop to ventilate, that's why rpms @ only 6,000..................

filthy phill
07-27-2017, 04:25 AM
not at those rpm and prop sizes you dont

LittleCharger
07-27-2017, 04:59 AM
not at those rpm and prop sizes you dont

Seems reasonable to me he's running a sst45 case

zul8tr
07-27-2017, 05:02 AM
45ss has 1:1 gears per APBA

http://www.apba.org/sites/all/files/documents/2015%20SST45%20TECHNICAL%20SPECIFICATION%20022515. pdf

with 12" pitch at 6000 and 1:1 gears theoretical speed no slip = 68 mph
61 mph slip would be 10.5%
His posted 61 would be reasonable. I have seen passes at 60 by GPS and that boat in the video is there.

sharpeye Mike
07-27-2017, 03:57 PM
Don't bother guys, simple Phill is pretty simple when it comes to math probrems

filthy phill
07-27-2017, 05:03 PM
there is plenty of posts and pics on other forums about this boat and motor,
go check out the pics of it with your sharpeye...
you obviously believe this is a genuine omc race motor .

I did not know that a shifting gearcase can be 1to1 ratio , I thought that was the non shifting special and rare gearcase.

MODIFIEDOUTBOARD
07-28-2017, 04:42 AM
In the VIDEO the Evinrude 45ss Osa ran had the original 45ss Gearcase with a 12p tunnel boat prop.

I mentioned to Osa that a nitro foot w/low water pu & 11 x 21 would carry that V-hull and not break loose as much........

This same motor in the VIDEOoriginally did 73 mph @ 7,200 in quarter mile drag on a 13' Tomcat Tunnel and dominated it's drag class in SE Virginia.

JohnsonM50
07-28-2017, 04:59 PM
the carbs talked about here are twin barrel carbs, no way to fit them on a twin cylinder motor.
they are for the v4 motors and have just the two bodies, 1 up top and 1 down the bottom.
Not true, I've done it. With some experimenting got it to work very well on a 31.8 OMC twin cross flow. It was within 1 mph on top & boosted mid range nicely. It also started better.
http://i35.photobucket.com/albums/d151/mes355/DSCN0835.jpg (http://s35.photobucket.com/user/mes355/media/DSCN0835.jpg.html)

JohnsonM50
07-28-2017, 05:12 PM
Not true, I've done it. With some experimenting got it to work very well on a 31.8 OMC twin cross flow. It was within 1 mph on top & boosted mid range nicely. It also started better.
http://i35.photobucket.com/albums/d151/mes355/DSCN0835.jpg (http://s35.photobucket.com/user/mes355/media/DSCN0835.jpg.html)

Thats a stock manifold. I removed single carb studs & shaved the aluminum down till it had a flat surface big enough to accept the 85hp 2 barrel carb. I made an adapter plate with 4 studs to mount the carb. There is a center block epoxied into the stock manifold to separate the barrels, 1 each cyl. The adapter plat is epoxied onto the cut manifold & thru screwed where the manifold studs were. a couple are under the carb so I used flat head SS screws there. It sealed right 1st try & ran 1st try. Next is going to be a V block reed set up but that will be more difficult. When done it will drastically reduce crank case volume & eliminate the pre historic 'wall' of reed obstruction.

JohnsonM50
07-28-2017, 05:21 PM
Thats a stock manifold. I removed single carb studs & shaved the aluminum down till it had a flat surface big enough to accept the 85hp 2 barrel carb. I made an adapter plate with 4 studs to mount the carb. There is a center block epoxied into the stock manifold to separate the barrels, 1 each cyl. The adapter plat is epoxied onto the cut manifold & thru screwed where the manifold studs were. a couple are under the carb so I used flat head SS screws there. It sealed right 1st try & ran 1st try. Next is going to be a V block reed set up but that will be more difficult. When done it will drastically reduce crank case volume & eliminate the pre historic 'wall' of reed obstruction.
http://i35.photobucket.com/albums/d151/mes355/DSCN0389.jpg (http://s35.photobucket.com/user/mes355/media/DSCN0389.jpg.html)

JohnsonM50
07-28-2017, 05:25 PM
http://i35.photobucket.com/albums/d151/mes355/DSCN0389.jpg (http://s35.photobucket.com/user/mes355/media/DSCN0389.jpg.html)
http://i35.photobucket.com/albums/d151/mes355/DSCN0449.jpg (http://s35.photobucket.com/user/mes355/media/DSCN0449.jpg.html)

filthy phill
07-29-2017, 05:21 AM
stop posting photobucket pics, they dont come out any more unless you pay for it.
none of these pics are now visible like they used to be.

JohnsonM50
07-29-2017, 06:19 AM
stop posting photobucket pics, they dont come out any more unless you pay for it.
none of these pics are now visible like they used to be.
, Yeah, I just found that out. As far as posting tho, I'll post as I wish & leave it to the moderators to notify me or block posts if I'm off base. As far as what can & can't be done depends on who wants to -not who says you can't.

filthy phill
07-29-2017, 12:21 PM
Wow got a.mind of your own hey .

That makes a change for USA and Canadian forums

Ketzer
07-29-2017, 12:40 PM
My nickname throughout high school and beyond was "Stick." I got that nickname as follows. I, at eighteen, was out running around town, late at night, with some buddies, and we were drinking massive quantities of Big Cat Malt Liquor. I, as usual, was passed out on the back seat of a '55 Chevy when the Cop pulled us over. Everyone got out, except me, because I was asleep, of course. The cop looked in at me and demanded, "Who is this?" One buddy said, "That's Steve," while another buddy said, "He's sick," at which point, the cop whopped me on the head with his flashlight and said, "Get out of there, Stick!" Thereafter, I was known as "Stick." How did you get to be known as "Filthy Phill"?

JohnsonM50
07-29-2017, 01:47 PM
Wow got a.mind of your own hey .

That makes a change for USA and Canadian forums

Yeah I do, & for whatever it's worth it IS mine to entertain. If you weren't so busy telling others how it is according to you you might find there's many very high caliber folks here but instead you choose to insult them. How did you come by the statement "P people off"? because it seems on purpose.

JohnsonM50
07-29-2017, 01:49 PM
My nickname throughout high school and beyond was "Stick." I got that nickname as follows. I, at eighteen, was out running around town, late at night, with some buddies, and we were drinking massive quantities of Big Cat Malt Liquor. I, as usual, was passed out on the back seat of a '55 Chevy when the Cop pulled us over. Everyone got out, except me, because I was asleep, of course. The cop looked in at me and demanded, "Who is this?" One buddy said, "That's Steve," while another buddy said, "He's sick," at which point, the cop whopped me on the head with his flashlight and said, "Get out of there, Stick!" Thereafter, I was known as "Stick." How did you get to be known as "Filthy Phill"? Good story Steve sounds like fun, not sure I want to know the answer to your Q tho LoL.

filthy phill
07-29-2017, 02:37 PM
at one point in the 1980's I worked on a good few tv and film sets and always carried a small video camera with me, at the time there was a fella in the usa called filthy phill who made porn films.
the producer I was working with saw my camera and said "oh look its filthy phill" next thing the name stuck for a while.
I had never heard of filthy phill and thought the producers was being very cheeky so went straight for him. other workers explained who filthy phill was then we all laughed it off.
But the name stuck ha ha producer's name was Peter Bennet, the tv series was Minder with George Cole as its main star.

MODIFIEDOUTBOARD
08-23-2017, 03:10 PM
62771

added a lot of punch out of turns