Boat engines and WOT

[Rob_Roy]

Originally Posted By: Nick R
Kind of curious, simply because depending on where we move, we may end up getting a boat. If we move to Ohio near Lake Erie we pretty much definitely would be. That's beside the point though.

It seems to me, with boat engines you pretty much would end up running WOT or near WOT all the time to get places. Is this pretty accurate? How do those engines hold up over time? Especially say the car engines stuck in a boat, like the GM 4.3L V6 that appears to be ubiquitous as boat engines. How do you run your boat?


Depends a lot on the boat. Ours has twin 7.4L mercs, and it easily comes up on plane at half throttle. 35 mph is an easy cruise at around 3000 rpm. Anything beyond that just burns more fuel. The engines in ours have almost 900 hrs and run excellent.

 

[Schmoe]

wow....twin 7.4's??? I'm drooling here.....nice.

 

[BigCahuna]

Drooling will turn into tears once you get to the gas pump.,,

 

[SteveSRT8]

Not if you really like boating.

I dropped some bucks into my sliver recently, about 200 bucks for a nice day of playing, tubing, racing, etc. Saw about 120 mph before I chickened out!

Well worth it IMO.

 

[hattaresguy]

Just run a fuel budget. Most of the power boaters I know just budget for it. $5k-$30k a year depending on the boat. Although one guy who died a few years back really loved his boat and burned $75k worth of diesel one year.

The sailors get to poke fun and say, ha my 50 gallons will last half the summer. Sure but your $7k carbon main will be shot after a few races.

So it all evens out.

 

[terminaldegree]

Exactly. It's just budgeting and priorities. People cringe when I tell them one hour at cruising speed on the family cruiser costs $125, but those same folks are spending $300 a night in a hotel next door for the same view I'm looking at while spending the night on the boat (not to mention paying for boat tours and fishing charters too). It's less excruciating if you think of it more as a summer home (and always buy used)...

 

[cchase]

We stick with waterskiing and tubing, and some pleasure boating.

It costs about $15/hour to do that. Cheaper than sitting in a smelly movie theater would cost for 4 people. Cheaper than sitting in your house smoking cigarettes cost many people per day.

 

[Stewart Fan]

Originally Posted By: SteveSRT8
Not if you really like boating.

I dropped some bucks into my sliver recently, about 200 bucks for a nice day of playing, tubing, racing, etc. Saw about 120 mph before I chickened out!

Well worth it IMO.


I've put $600 worth of gas into mine in the last couple days.

 

[SteveSRT8]

Originally Posted By: Stewart Fan
Originally Posted By: SteveSRT8
Not if you really like boating.

I dropped some bucks into my sliver recently, about 200 bucks for a nice day of playing, tubing, racing, etc. Saw about 120 mph before I chickened out!

Well worth it IMO.


I've put $600 worth of gas into mine in the last couple days.


I honestly wish I had enough time to do that! Maybe when I retire. But any boat remains a very inefficient way to burn fuel for sure.

 

[car54]

I have a 2012 Larson LX950 19.5' with the mercruiser 4.3 MPI and it is very fuel efficient at a 3000-4000rpm cruise. Ive used WOT, but last time I scanned the ECU it only had 20 minutes of runtime at WOT. No need to, it only goes a few mph faster and makes a lot more noise. It gets up on plane easily with no wot as well. I would call it the perfect engine/boat combo. excellent economy, and 4 months after buying it have 65 hours on it.

 

[Barkleymut]

My 2stroke Mercury 50HP pontoon doesn't get anywhere fast and drinks just over 1.5 gallon at a steady 4,000 RPMs. Of course we have a free place to stay anytime we want on a big lake that we know very well. Really we just take it out to the middle of the lake and let the kids swim, sometimes I take it around to do some fishing. Tubing isn't all that fun since it goes 18MPH at top speed lol. But that is what we have a sweet PWC for

 

[hattaresguy]

Ugh catalytic converter manifolds, the Coast Guard tried for years to stamp out that nonsense.

Hopefully its a freshwater boat, in salt they are shot in 5 years.

Its also raw water cooled! I hope its a lake boat.

I wonder how hard it is to ditch them when they go bad? I suspect its very easy.

 

[Geoff]

Depends on the boat. With our wakeboarding boat we rarely exceed 3000 rpm. Wakeboarding and surfing are not fast moving activities. Cruising is very relaxing at 15-20 mph.

With a sterndrive, cruising is often 28+ mph (usually 3000 rpm depending) because the boats run bow up at slower speeds and wander, even when trimmed down.

BTW we have cats on our motor and no fumes. I like them.

 

[cchase]

Originally Posted By: Geoff
Depends on the boat. With our wakeboarding boat we rarely exceed 3000 rpm. Wakeboarding and surfing are not fast moving activities. Cruising is very relaxing at 15-20 mph.

With a sterndrive, cruising is often 28+ mph (usually 3000 rpm depending) because the boats run bow up at slower speeds and wander, even when trimmed down.

BTW we have cats on our motor and no fumes. I like them.


What type of boat are these 28 mph stern drives attached to, by chance?

I only ask since the majority of stern drives I've experience with, in the 17-21 foot length range, plane at 18-19 mph with no issues.

 

[terminaldegree]

I remember a 2001 sea ray 280 sun sport my parents used to have (twin 350's/bravo 1's). That boat wouldn't plane well at all until you're doing 2800 rpm or so at about 28 mph with drive and tabs fully down.

Other than that transition-to-plane rpm range and wide open throttle, minimum planing speed for a typical v-hull is one of the least fuel efficient ways to run a boat.

 

[matt711]

I have a 22 foot bay boat with a 250 Suzuki 4 stroke. May rpm is 5800 and around 57 mph on the gps. I can maintain plane down to around 2300 rpm and that is good for around 22 mph. My sweet spot is 4000 rmp at 42-44 mph.

 

[Silverado12]

Originally Posted By: Schmoe
That's SAH-WEET.....would love to have stainless steel manifolds but, that's not going to happen. My 96 Merc....still got original factory manifolds AND impeller....believe it or not. Nothing but lake water and boat is not stored in water during summer, always pull it out and park with drive down resting on a piece of plywood to take the tension off of the rams and outdrive mounts. The 888 is what I cut my teeth on.


The impeller is easy to replace. There are 6 bolts and a quick release on the speedo tube. One bolt hidden under the anode. One o-ring has to be checked for proper alignment as it has a tendency to come off when the lower is removed. Four bolts hold the impeller cover on. Rebuild kit about 25 bucks. Remove-reinstall with the prop off to lighten the weight a little.

 

[Silverado12]

I have a 1999 Chaparral 18' with the 4.3 and Alpha 1 Mercruiser outdrive. It likes to cruise at 30 mph. WOT it runs 55 mph if I play with the trim. I don't run it wide open much, but I like to have a little fun with the top speed every time I take it out for a few minutes. Last time I checked compression it was around 160 on all cylinders. Uses no oil and the oil I use is 15w40 Rotella with an ACDelco PF-47 filter.

 

[Turk]

My 2003 140HP Suzuki 4-Stroke maxes out at 6,500 RPM's.

...and you should hear her sing, wow, does it sound fantastic!

 

[Nick R]

Heh, a few months ago I visited a friend near ithaca when he and his wife drove up from texas to visit their family. His grandfather owns a lake house on one of the finger lakes, and his dad owns a Jet ski. that thing was a lot of fun, it has a 1.8L Yamaha engine. I found it interesting that you have to keep it above about 4,500RPM to even get much semblance of forward motion. Man that thing was thirsty!