Yamaha 25 HP mod

Hi everyone,

I wanted to mention a small mod that seems to have fixed a very stubborn problem with a 2005 25 HP 4 stroke Yamaha. Several people had worked on the carb including the dealer that sold it. It never ran well for more than a few weeks whenever the carb was done. Eventually a new carb was purchased and installed. No better results were had and it was done several more times over the course of 4 years.

In march a man who lives in Sebastian tried boring out the high speed jet by 3.5/1,000. Since that time the engine has been used several times a week and almost daily this summer with no more problems. I wouldn't recommend this to others unless you have had ongoing problems with a carburetored engine.

Best regards,Frank_S

 

Hi DH,

The engine would surge during acceleration and did not have a top end near what it should, even with a very light skiff to push. The first few times after a carb cleaning it would do better, but was never right. It now continues to run "near normal", but the HP curve is still on the anemic side for a 25 HP. I ran my 8 HP Tohatsu 2 stroke on the same boat (it is used to collect bait from pigfish traps) and it wasn't that far behind the 25. The engines we have had the most trouble with are small Yamaha 4 strokes. I know the problem is fuel related. I am driving to Melbourne to buy no ethanol fuel friday. Three of us are going with about 45 gallons of fuel capacity in the gas cans we have bought and borrowed.

I suppose we are legal to haul it in a pickup with a cap on it?

Best regards,
Frank_S