routine maintenance

Post here for issues with outboard engines (i.e Yamaha 9.9) on PDQ yachts
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bg5w
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routine maintenance

Post by bg5w »

The previous owner replaced the 9.9 Yamahas with 9.9 Hondas with hydraulic lifts. I decided to change the oil, filter, spark plugs, fuel filters, etc. It turns out I cannot access the spark plug on the port engine, or fuel/oil filters on the starboard engine without pulling out the engines. I cannot even remove the side cover on the outboard side.

Is this predicament true of the Yamahas, as well?

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Re: routine maintenance

Post by doubledutch »

On the Yamaha the engine in the half tilt position allows reasonable access to plugs.

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Re: routine maintenance

Post by amytom »

Even with the Yamahas it's a good idea to pull them once a year. That's the only way to get to the gear oil in the lower unit.

Also allows for a thorough clean and lube of the bracket assembly to reduce corrosion.
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Re: routine maintenance

Post by mikeandrebecca »

...and change the impeller. Just tackled that job. :(

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Re: routine maintenance

Post by mikeandrebecca »

As doubledutch said though, plugs, etc can be accessed without pulling the engines.
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Re: routine maintenance

Post by thinwater »

You can do all of these jobs in the water...

http://sail-delmarva.blogspot.com/2011/ ... pumps.html

... though during a painting haul-out is better.
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Re: routine maintenance

Post by mikeandrebecca »

Show off. :wink:
bg5w
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Re: routine maintenance

Post by bg5w »

Thanks for the input thus far. I hope I never see the day where I have to pull the lower unit while in the water - I see little pieces everywhere going to the bottom.

The new 9.9's have what is called a dual thrust propeller which directs the exhaust away from the prop. They claim a 60% increase in thrust in forward with this prop. This would surely be noticable. Does anyone have this prop and noticed the difference? Has anyone replaced the prop on an older unit with this prop for more thrust?

Thanks,

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Re: routine maintenance

Post by Page 83 »

Every other manufacturer scrambled to come up with a competing claim to counter Yamaha's high thrust design. Unfortunately, they would have had to redesign their lower end to accommodate a bigger diameter propeller with more thrust. They all settled for a new decal instead. :wink: We don't buy enough engines to be worth the expense of retooling.

The most important factor to consider is the boat speed needed for their engines to develop best power. For our Yamahas that is about ten knots, which we can get close to while motor-sailing. For Honda, Mercury, Suzuki and Tohatsu, it's over 15 knots. At full throttle, our typical bare pole speed is around 7 or 8 knots. At that speed our High Thrusts are delivering about nine horsepower at 5300 rpm, but the others are much further back on their power curves, producing less than seven horsepower. I you have higher rpm at this speed, the props are ventilating, or even cavitating.

Outboard motor construction quality has peaks and valleys; Honda is in a slump*, Suzuki is on the rise, small mercury engines are Tohatsu's with a coat of black paint Yamaha is managing to hold on to a good reputation, as are the Tohatsu/Mercuries.

*Name brand loyalty to Honda continues to sell their outboards. Unfortunately, the quality of their cars, motorcycles and generators doesn't extend to their outboards. By the same token, Suzuki's are underrated because of their cars. Tohatsu has always been a reliable, no-frills manufacturer. People who wouldn't take a Mercury on a bet (see above) are very happy with their Tohatsu outboards.

I you have a folding bimini, you can hoist the engines out of the wells with a halyard, just high enough to access the plugs without disconecting the Morse cables.
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Re: routine maintenance

Post by thinwater »

We've noticed the newer Yamaha 9.9s don't have an accessible oil filter. Ugh. I assume folks are simply changing the oil more often?

Does the strainer on the pump foul, or are the engines too new for that to be known?

I've only had these engines ~ 10 months and so I've not really dug into their service needs. I've got the manual and will read it in 4 months when I haul out for paint.
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