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I just scored this super clean old trihull with a 70 horse triholer on it. The boat resided in eastern Oregon at 4500 ft. in elevation and was tuned for Phillips lake there. I fired it up in the tank down here and it ran like a top. My question is, do my carbs have fixed jets or am I tuned way to lean [for elevation] to run down here at sea level?
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I never dealt with the elevation thing. I can however tell you what the jets would be direct from the factory (sea level). Model number? -
Joe, Thanks so much for your reply.model # is706730, ser.# J0012775.
I'm assuming these are not adjustable jets and that it would be unwise to run the [high elevation, "lean" jets], down here at sea level due to inadaquate lubricating.
I'm also curious as to how much work is involved in changing the jets back and forth. I once took my fishing boat to 5000 ft.on a high lake, the big motor ran like a toad, the kicker I simply "leaned out a bit and it ran fine.f you dont mind me asking, What is the procedure for swaping them out? Thanks for your help, I'm really excited about the potential for this old girl, the paint looks almost like new and the ring gea looks new too, maybe they started it with a rope! LOL.Comment
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706730 = 1976 70hp Evinrude ....... Factory Shipped Jets
Slow Speed Jet = 317473 = .030 = ID marked on face of jet as 30.
High Speed Jet = 321407 = .054 = ID marked on side of jet as 54D.
There is no Intermediate jet.
SS jet is behind screw at top front of carburetor.
HS jet is in center bottom of float chamber, in back of the drain screw.
No need to remove or dismantle carburetors to change jets... simply remove screw, remove jet, install new jet, etc etc. However you will need a screwdriver with a shank that will just miss the 1/4x20 threads of the drain screw/float chamber with the shank having the tip shaped as what you see here.
Don't trust the present jets if they are marked as I note here as they may have been drilled out (that happens a lot). Check them first with the proper size drills to see if they were indeed drilled oversized.
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Many thanks
I want to thank you for the great info. This is my third looper I've owned in the last 30+ years. I keep thinking I aught to opt out for a newer 4 stroke like everybody else but the incredible service and quality of these old girls, keeps bringing me back. This one is so clean I'm thinking it might be the last one I'll need on my fishing boat. I'm excited about learning more about caring for this old girl so I don't have to trust it to others. Thanks again Joe for your help. DonnyComment
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