Efficiency of Twin Yamaha 200's on Coastal 2600

[Mr. Ross]

Perhaps I am a bit optimistic, but I am looking for a fuel consumption comparison for twin 200 Yamaha outboards mounted on a Coastal 2600 as compared to my current boat, a 29' Silverton with twin 198 HP inboards.

The Silverton is beamier, heavier and three feet longer. Utilizing the formula for fuel consumption I found searching this site, the GPH look to be similar. That is OK by me, I just don't want to get into increased fuel usage.

The Wellcraft is considerably lighter than the Silverton so it may be beneficial since the formula does not take that into account.

After all of this, does anyone have any input about the reliability and serviceability of those engines? I like to do my own work but have never really done much with outboards except change plugs. I do ALL of my own inboard work so on the aptitude end, I can comprehend most of it.

The reason I am making the switch is due to my heath. I can no longer perform the physical contortions in the bilge necessary to work on inboards or I/O engines and drives. In addition to that, I want something that is more trailerable than my larger boat. I can sneak a 9' beam down most roads in my area without an issue.

 

[WillyBWright]

Re: Efficiency of Twin Yamaha 200's on Coastal 2600

Carbureted, EFI, or HPDI 2-stroke? Four-stroke? With carbureted and EFI 2-strokes I'd expect increased fuel consumption. With HPDI's and 4-strokes I'd expect similar fuel consumption. But only if comparing different power on the same hull. Change hulls and all bets are off. Weight is one factor. Hydrodynamics is another. Get yourself a good service manual. They're a totally different animal than you're accustomed to. They all use gas, have sparkplugs, and propellers. Most everything beyond that is a world apart.

 

[Mr. Ross]

Re: Efficiency of Twin Yamaha 200's on Coastal 2600

I have yet to inspect the internals of the engine so I am uncertain if they are carburetor or injection. I was going to do that today but we woke up to another ten inches of snow. They are two-stroke. I imagine the boat weighs in at a couple thousand pounds less and considerably less wind resistance due to lack of a fly bridge.

I have been unable to find much negative about the Yamaha outboards, so that makes me fell fairly good about them.

 

[Mr. Ross]

Re: Efficiency of Twin Yamaha 200's on Coastal 2600

Well, I was able to get into the boat and inspect her yesterday. They are carbureted. not injected. Also appears to have oil dripping from the starboard engine near the gear housing, I believe it is gear oil. Possibly a seal?