Increase HP of current outboard

[LONG_KEELER]

I have an 4hp Mariner 4T outboard and would like to increase it to 6HP .

It seems that this is possible , particularly with a "family" group of outboards i.e. Mariner 4/5/6hp and family of 2T , mainly base Tohatsu/Mercury/Mariner, Yamaha engines

Would be interested if anyone has done it, and if they noticed any difference.

Seems that some engines just need a different carburettor and others removal of the air restrictor in the carb plus a few easy adjustments.

Would be a nice lockdown project

TIA

 

[rotrax]

Check the throttle butterfly opens fully.

Our 4HP Suzuki 4T can be easily converted to 5HP by a new stop bracket that allows full butterfly opening.

I gave the price of the bracket an old fashioned look - 12 quid plus vat - and gently bent the existing one to allow full throttle.

It will go to 6HP, but that needs a new carb.

 

[LONG_KEELER]

Check the throttle butterfly opens fully.

Our 4HP Suzuki 4T can be easily converted to 5HP by a new stop bracket that allows full butterfly opening.

I gave the price of the bracket an old fashioned look - 12 quid plus vat - and gently bent the existing one to allow full throttle.

It will go to 6HP, but that needs a new carb.

Good to know. Thanks.

 

[MonniotC]

I don't know about current models, but I have a Mercury 4ML Sailpower, purchased new in 2006. The dealer (a large main dealer) said he could convert it to 5hp at no cost. Just a matter of removing a nylon throttle-stop from the carb. He also assured me that doing so would not affect the warranty.