Am I Underpowered?

[longshanks]

Re: Am I Underpowered?

I might as well punt this one back to the top again...

My motor made it into the shop this week, and before they even put it on the dyno, the computer showed a fault with one of the coils/spark trigger. Apparently the motor was misfiring, and the shop tech found a lack of spark to at least one cylinder.

So they have ordered a new coil, and are going to put this thing on the dyno, once the part is replaced. The very last time I ran the motor, I noticed it misfiring, but this had never been an obvious problem to me earlier. Not to mention, if this problem was present earlier on, I question how it made it past the shop that worked on it before...

I sure am glad that it isn't prime boating season here. And I'm glad it's still under warranty. Going on 11 months now with no reliable service from this motor!

 

[1730V]

Re: Am I Underpowered?

Keep us posted. The dyno will take the mystery out of it.

Is it possible this engine has the wrong gears in the lower unit? It's obvious this engine has been a problem child since day one.

 

[longshanks]

Re: Am I Underpowered?

Ok, so here's some good news to wrap up the boating season...

Mercury replaced the 'faulty' ignition coil. I have no idea how this part failed, but chalk it up to the ongoing saga I've had with this motor. The part was replaced under warranty. In a nutshell, after changing this part out, the motor runs considerably different, and there is a significant power increase.

Holeshot went from 10-15 seconds, down to about 4 seconds

Midrange is now much more 'punchy' -- my dog doesn't like it...

Top speed went from 26mph to 30.5

RPMs went from peak of 5200 to around 6150

If this motor wasn't under warranty, I would have had to sell it long ago, accepting a significant loss, as I wouldn't have been able to afford ANY of the spendy repairs that were done on it. How this problem went so long, undiagnosed, by Mercury mechanics, I have trouble understanding.

But it seems to be fixed. I am running a Vengeance SS 11 pitch prop, 1.83 gear ratio, doing 30.5mph at 6000 rpms. This translates to about 11% slip. This performance is pretty much what I expected from this setup, and I may be able to milk a bit more speed of it by going up in prop pitch a little, but not much.

Thank you for all the input you guys have provided, it was helpful to me, in getting through the many problems I've had with this motor.