New outboard motor on the way

[Diamondjet]

bigger carb = more hp

Hi Sumner...I was told the same thing at the St. Pete boatshow this year. Bigger bore and bigger jets equal 4,5 or 6 hp depending upon your needs. Same power head on all of these for the Tohatsu-Nissan-Mercury line. We only need 4hp on our lake but in retrospec I wish I had paid the extra for the 5hp version. I still have some confusion on which jets and what size are used on the carbeurators. As pointed out in a earlier post the "slow jet" and "pilot jet" are the same item. At the boatshow a tech for mercury showed me that idle problems are often associated with the jet under the brass plug and that is not the same but appears to have an influence on the idle circuit.

 

[Sumner]

Hi Sumner...I was told the same thing at the St. Pete boatshow this year. Bigger bore and bigger jets equal 4,5 or 6 hp depending upon your needs. Same power head on all of these for the Tohatsu-Nissan-Mercury line. We only need 4hp on our lake but in retrospec I wish I had paid the extra for the 5hp version. I still have some confusion on which jets and what size are used on the carbeurators. As pointed out in a earlier post the "slow jet" and "pilot jet" are the same item. At the boatshow a tech for mercury showed me that idle problems are often associated with the jet under the brass plug and that is not the same but appears to have an influence on the idle circuit.

On the bore your talking the carb bore and not the cylinder bore.

I'll bet when these outboards are used on a sailboat the difference between the 4-5-6 would be really hard to distinguish. If you had them on a small boat and were trying to run at max RPM/HP to get up on plane then the difference might show up.

We put a higher thrust prop on our 5 HP ....

7.9" Dia. X 6.0" Pitch 3-Blade

... and kept other with us as a spare.

and later found out that we could of even put the higher thrust prop that comes on the Sail Pro .....

8.375" Dia. X 6.0" Pitch High-Thrust 3-Blade

I think running one of those on the 4 or 5 HP would make more difference if you have the common 8 pitch on them now. They are available from onlineoutboards.com,

Sum

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[Diamondjet]

Finally got the Nissan 4hp on the lake last Saturday. Idled great. No issues. Now how long will it continue? Only non-ethanol gas in this puppy from now on.