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Thread: omc triple 70 carbs

  1. #1
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    Default omc triple 70 carbs

    so I know it has been debated on here plenty about what omc triples came with the biggest carbs. I have a buddy that just got a 1988 60hp and was after the better carbs. So I finally pulled a top carb off each engine I have and measured throats on them. My 1992 evinrude 70hp on my boat currently measured 38mm/1.5inch on the air inlet side, the outlet engine mounting side measured 35mm/1.4in. I compared the part number on the carbs 434160 to make sure that they're originals which I believe them to be engine is stock as far as I know to parts diagrams for my 1992 70hp model #E70TTLEND. I didn't really know where to look to try and verify that my block is original, and that it hadn't been replaced with some reman powerhead from a different year. It had a casting number on it of 334474. Well the part numbers as best I can find on my carbs they would have been original to my engine so they are as far as I know 70hp carbs and most likely bigger than 60hp carbs.

    Strange thing is that my buddies 1988 60hp his carbs measured the same so I wonder if someone had already changed them before. It's hard to say as the 1988 he got it cheap and very well might not be all original. He also bought a set of carbs on ebay that claimed to be off a 1987 70hp and they came in and measured the same as the ones off his 60hp, and my 70hp. So at this point I'm thinking he already had 70hp carbs on his 60. Now this is weird too I have a 1987 stock 70hp model number E70TLCUR, sitting in my garage that is the one I plan on building at some point maybe if life ever permits messing with it. To my knowledge it appears to be all original outside of vro delete done sometime in the past. I took the top carb off it the inlet side of the throat measured 38mm/1.5inch and the engine side measured the same as well. So it appears to have the largest carbs. What's weird is the carbs my friend bought off ebay seller claimed they came off a 1987 70hp evinrude but yet they are the slightly smaller ones like on my later 1992. Now I know it's hard to say if the sellers claims are true or if they were the original carbs off a supposed 1987 70hp. So in my eyes the carbs to be after would be the slightly larger ones like my 1987 has. The only disadvantage I could see to them is they only have a main jet and low speed jet no idle jet or idle adjuster needle. In the case of my 1992 carbs they have high and low jets and a idle adjustment needle valve. Anyways if anyone else wants to weigh in as to what they think are the best triple carbs and include pics of their carbs or ones they have had please do. To me it would seem the best ones to have would be ones with the larger 38mm/1.5inch inlet and outlet, and with a idle jet as well as low and high speed jets if omc ever made such a carb. Part number on the 1987 carb was 431705 fyi.

    If my knowledge and understanding is correct my 1987 is a 56ci permanent cast bridgeport. It doesn't have the casted in webbing between cylinder head and exhaust housing area. My 1992 should be a 56ci bridgeport lost foam casting, which it is definitely a lost foam 56ci idk if it's a bridgeport for sure in 1992 it should have been assuming it's the original block. Pictures of the larger 1987 70hp carb with fixed idle jet circuit.
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    pictures of the 1992 70hp carb with idle adjustment needle measured 38mm/1.5inch inlet measured 35mm/1.37inch outlet so slightly smaller than my 1987 70hp carb. Also picture of block casting number on my 1992 maybe someone on here knows how to date to know for sure it is a 1992. pictured below is 1992 carb I took a picture of the casting number on the top which was the same on each carb.
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    Team Member hupiveneilija's Avatar
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    Those on the upper post are the best so far ive driven on my motor! I had 2cyl 1.5in before those and throttle response is like night&day with current ones! Also 1.37in w/o idlejet is good for response allthough little less power.
    Idlejets and needlescrewes are for emission purposes i think. But all in all changing from 1.37in to 1.5in, difference is noticeable!

    -J-

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    Team Member LittleCharger's Avatar
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    You need to measure the Venturi to see the difference between the 60 and 70 carbs
    Likes hupiveneilija, fs5, Powerabout liked this post

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