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Yamaha 2.5 HP Four Stroke
35.0% of users recommend this

Express238's review of Yamaha 2.5 HP Four Stroke

“Know the pros and cons before buying”


written by Express238 on 29/09/2021

Bought the newer 2015 version this summer used. Also have the 4 HP purchased new in 2002. The 4 HP has a lot more power to push our 27’ ULDB race boat over 5 knots easy. While the 2.5 HP works just well enough up to 5 knots maximum. The 2.5 HP is very fuel efficient at 4.5 knots.

The 2.5 HP has an extremely fine pilot jet that clogs easily. A partial clog will make a smooth idle at low RPMs difficult to achieve. All summer the motor started first pull - but required a higher than optimum RPM. Just brought home for storage, the motor stalled while being flushed. Problem was a fully clogged pilot jet. The ride home must have stirred up some debris in the float bowl. Used a very fine wire to push the clog out - as carb cleaner alone was insufficient.

Once all the various carb jets have been fully cleaned, the motor now runs like a champ. Oil change was easy. Leg oil change was easy. Carb took a few hours to liberate, clean, reassemble, and water tank test. Repainted small paint chips, waxed painted surfaces, and conditioned plastic. 100% worth the time and effort - as the motor looks and runs like new.

Was probably the reason why the previous owner sold this motor. Inconsistent low idle. Now fixed. We will use the 2.5 HP all the time moving forward as it is a 20” vs our 4 HP 15”. The 15” short shaft is however perfect on our inflatable. Know the pros and cons and how to fix them - and you should be good.

If you need a reverse gear and a bit more power - get the 4 HP. If not the 2.5 may be all you will ever need.

  • Value For Money

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