Honda Carburetor Jets

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ppine

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I have a Honda 4 stroke made in 2000 that is a long shaft 8 hp used for a kicker motor on a fishing boat.

It performs well and is dependable but does not start on one pull. Reading the owner's manual, there is a description that suggests that for use over 5,000 feet the carb jets should be changed out to account for less oxygen above 5,000 feet. I live at that elevation and fish mostly on lakes from 5,000 to 7,000 feet. Sometimes I like to run places the Sacramento R for salmon at several hundred feet. I am planning a long trip next year to Roosevelt Lake, WA which is only around 1,200 feet.

Anyone else have issues with elevation and starting a modern 4 stroke outboard?
 
No, but "elevation" here ranges from 290 feet to 1200. Hardly worth mentioning.

5000'+ yes there's considerably less o2 in the air and a jet change may be required. However...I'm not sure how much difference there'll be in the starting. It "should" start easier with elevation due to a slightly richer mixture caused by less air. It'll just run a little richer at all engine speeds. That's not necessarily a bad thing, but where the problem I see with powersports stuff is when people change to high altitude jetting, then forget to change it back once they get back here (about 350' MSL), and the engine runs lean. It used to be a bigger issue, but nowadays with EFI, it's become mostly a non-issue.
 
Thanks for the response. Fuel injection solves these kinds of problems but the world is still full of carburetor outboards. It will be for decades to come.

My main is a Yamaha 115. It seems to run fine everywhere.

The little Honda has power and idles good. It is just harder to start that I would like. I used to run an old Johnson from the 1970s at Lake Tahoe at 6,300 feet on a sailboat. It was a one pull motor at all elevations.
 
After further inspection, I have discovered that the quick connect fitting on the fuel line to the portable ob tank is leaking air. I am going to replace it which should make a big difference.
 
My old Honda 7.5 was never a first pull motor. Whenever a dirt bike, lawn mower or outboard won't fire real easy once warm or needs choke then it's low speed is too lean. First thing to do to any Honda motorcycle with a carb is to go up a size on the low speed jet. Even tho you are altitude I'd go up vs down in jet size on the low side unless it's chugging rich. When cold if you have to keep the choke on or half on for more than 10 seconds after it fires that is the first sign it's too lean. I can tell if a motor needs a bigger low speed jet or adjustment in 15 seconds after it fires. If it need a lot of choke after it fires it's lean. Could be just dirty because that makes them lean as well.
Another trick on inherently hard to start motors that require 3 or 5 pulls or kicks is to forget about trying. Just kick or pull it easy so you don't wear out the starter. After a couple easy pulls let it rip and it will start. I learned that watching little tiny kids start big dirt bikes or outboards. Bunch of easy kicks or pulls draws in fresh air and fuel. The old stale crap in the intake and engine is too foul to start first pull. The clean fresh air fires on the 3 or fourth easy pull.
 

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