RPM Operating Range...Yamaha 4-Strokes.

[magicalbill]

I have wondered about this for awhile.

What is the best extended-cruising RPM range that will extend the life of my 200 4-strokes? I don't want to run them too high for extended periods, thereby shortening the lifespan.
My extremely reliable tech says that it's good to run the 4-strokes at higher rev's some of the time.

They are on my 2007 Gulfstream. Usually I cruise at 3500-3900 if the seas allow. Occasionally I outrun a storm cell, or need to get home and punch it up to 4200-4400, but never higher than that.

What do you all run yours at?

 

[fishingFINattic]

I fish on two boats with four strokes -
The one with F150's cruises at 4400 to 4600 all day long -
The one with F250's cruises at 4800 to 4900 all day long-
These are both boats that throttle up and run 100 miles one way to the New England canyons.
These numbers seem high to me - But that is what they do and have done for awhile!
Tim

 

[gerrys]

At 629 hours of total operation, my Yammi F225's looked like this on my 2004 Marlin:

< 1000 hrs 253 hrs 40.2%
1000-2000 188 29.9
2000-3000 30.8 4.9
3000-4000 12.1 1.9
4000-5000 125.5 19.9
5000-6000 20 3.2
>6000 0 0

We have a short distance to the fishing grounds and spend a lot of time slow trolling or drifting with the motors running.
This info is available when you hook your motor up to a pc and use the yammi software.
I haven't downloaded my F250 on my Ranger Bay boat but I can tell you the numbers will not look at all like those shown above. I don't have any issues with cranking it up at 5800-6000 and moving along at 50+mph. Those Yammi's are tough and will take it all day and night long. Keep your oil and filters changed at regular intervals and throttle up.

 

[ocnslr]

About 735 hours on the twin F150s since repowering in Nov 2005.

We run at 4500-4800 anytime, and no problem with cruising at 5000-5200. Have run just a notch under WOT for the last hour of a trip in from offshore to make the weigh stations with our citations before they close.

Brian

 

[Tuna Man]

I run my Marlin with F250 between 4000 and 4500 most of the time. I have no evidence to prove my theory, but I feel that most gasoline engnes will last the longest if they are operated in their 'sweet spot.' On every Grady I have been on (20' CC to 30' Marlin) they always seem to run best (when propped properly) between 3800 and 4500. I can only assume that running at a higher rpm will shorten the lifespan of the engine. I assume with higher rpms comes hotter engine temperatures, more strain on powertrain (crank, rods, pistons, etc), lower unit, oil breaks down faster, etc.

Not sure this is a fair comparison as it is such an extreme example, but dragsters only make a few runs after their engines run at say 12,000 rpms before the engines get replaced. I can only assume that if I ran my boat at max rpm (6000) whenever possible, the engines would not last as long as if I were to run them at 4000.

 

[Fishermanbb]

I actually think you may be running yours too low at cruise. Remember, 4 strokes are designed to develop more RPM than 2 strokes. I've had several 4 strokes (3 on current boat) and they all cruise 4600 - 4800....Which is just slightly below 3/4 throttle. Some guys I know run them faster than that with no problem, but, like you, I like to take it easy on them.

You can check with Yamaha but I believe you will find that for the 200 - 250 HP motors cruise RPM is in the range I specified.

 

[Tuna Man]

Fishermanbb,
I think you are writing to me about the 4000-4500 rpms. Maybe you are correct, as I would like to feel confident I am not doing any long term damage runing a little faster when conditions permit. Just as a side note, I also have been told about the 3/4 throttle 'rule.' Wouldn't that be 4500 on a 6000 rpm max engine?

You go me thinking, maybe I can cut down running time on those 100 mile canyon runs now...

 

[megabytes]

I run my 300 with 225s up to 4700 for extended periods when condtions permit. Above that I can see the MPG drop quickly. I will run WOT for 109 seconds on occaision just to exercise the engines. My dealer told me that Yahama says to "run them hard" so I feel 4700 is OK.

BTW: at 4700 with full load, water, fuel, 4 persons, genset, I can run 27-28 kts with 4 bars of trim.

 

[Fishermanbb]

I was responding to the OP but I believe it applies to you as well...But I was recommending 4500 - 4800....Seems like that is the recommended range for the 250's....You should check on the 200's just to be sure....At 4500 you will still be taking it easy on them and you will pick up significant speed over what you are currently running.....I'm not sure but I'll bet your economy is similar or even possibly better....Make sure to check MPG's Vs. GPH......

The 232 will sing right along at 4500 with no problem.....I had one with 150's (NOn Cv2 and 2 strokes) and it was a fantastic boat......Check with your dealer but I'd say crank those 200's up a bit and get to the fish a little faster....

as for the 300....Had one of those as well but it had 2 stroke 250's so I ran around 4000 - 4200.....My friend has one with 225 4 strokes and runs 4700 all day long with no issues......

 

[magicalbill]

Thanks all..
This is interesting stuff. I wasn't aware that you all run them that fast with no problems.
If I crank up to 4500-4700 or so, I'm at 35-37MPH.

Do they use any oil over time between your oil changes at those sustained rev's?

 

[Lainie J]

I run my Marlin with 02 225hps at 4K most of the time. That seems to be the best fuel burn at 15 gph and 23 K depending on weight. a few year back I came back from 35 miles offshore to make a tourny deadline at between 4600 and 4800 and she ran great all the way with 4 guys, plenty of fuel left and a 450 Thresher. And yes made back in time to take first.

 

[wahoo33417]

I try to run at what seems to be my most efficient cruise of 4,000 rpm (about 27 mph). I figure it is the most efficient speed for a reason. Of course, like most, I've held 5500 - 6,000 rpm for awhile when a lightning storm was gaining on me!

Rob