Mariner 3.5 - fitting 5hp carb?

[SimonCh]

Hey,

Has anyone used one of the kids for a 4-stroke mariner 3.5 to convert it to 5hp? Wondering how much success you had?! Tempted to buy one as my engine is now out of warranty and i'd like my tender to get on the plane.

cheers,

Si

[Limecc]

Hi Si, I purchased the ReadySetBoat kit from the US which is effective but overpriced even though it wasn't caught by customs. Better to source an alloy prop and carb separately. For example I got a higher pitched alloy prop for just £12 (delivered) from Ebay.

I was expecting a higher pitched prop and the kit one was actually less than the plastic OEM. The 5hp carb has the same venturi size, the difference is in the jetting. I would go for a 6hp carb, and the Chinese Mikuni clones seem to perform faultlessly.

I've used it as an aux motor and it develops so much power at full welly it sucks air down and loses grip. I can't lower the motor any more so was considering fitting a doel fin. I think it would make a SIB fly.

New decals make it look the part:

[Tommy c]

Does this actually achieve the same results as a purpose built 5hp?
I understand the metal prop is to eliminate any flex the plastic one may have.
Does a bigger carb just increase revs?

[beerbelly]

i fitted a 6hp carb to mine and it over fuels stinks rich and i used a full tank of fuel in an hour i ended up putting the 6 carb on my 5hp and the 5hp carb on the 3.5 much better

[Tommy c]

Originally Posted by beerbelly

i fitted a 6hp carb to mine and it over fuels stinks rich and i used a full tank of fuel in an hour i ended up putting the 6 carb on my 5hp and the 5hp carb on the 3.5 much better

Do you actually get any better performance or speed from the bigger carb

[beerbelly]

i wouldnt say a great deal no .it probably is slightly better what i did notice is the huge flat spot/stumble just of tickover was gone