What is the max rpm you run your motor at continously?

[cmarkphillips]

I read a post somewhere, possibly another website, where a skipper ran their Yami F115 at around 5200 rpm most of the time and never had a problem with the motor. They reportedly had over 1000 hours on it before they repowered to a larger motor and not because they had any problems with the motor.

I was wondering what rpm people that are traveling pretty far out to fish run their 4 stroke engines and how have their motors been holding up?

 

[Whitto]

I run my motor at WOT every chance I get.

I don't have a fourstroke, but an Etec and they just love to run hard.

The right prop makes a huge difference to the life of any outboard, not to many RPM and not to few (Low RPM at WOT is the worst thing you can do to an outboard)

 

[Jim Jenkins]

Max RPM Continously

If seas permit, I will run around 4000-4200 RPM. According to the engine test of the Yam. 150 four stroke, the best fuel economy, ie. mpg is 3,600 rpm.

WOT for my 195 CC w/ T-Top is 58-5900 RPM turning a SS four blade Mich. Wheel 14 3/8 X 18
This will give 42 mph by GPS. Med. to light load.

 

[cmarkphillips]

I appreciate the responses as I have wondered if I have been in a sense babying the engine and worrying about hurting it in the long term when in reality running it in the 75% to 90% rpm range won't have any negative long term effect - other than additional fuel consumption.

I hear you Whitto about the prop making or breaking an engine. I've already test a couple of props - unfortunately none of the props I've tested add any additional hp to the engine, which is what I really want.

Jim, thanks for the performance numbers and specs as it provides "real world" numbers. I run normally between 4-4.5k, but as I am running an older Honda 130. The only time I see 40 is when I'm trailering down the highway. Some days I day dream about repowering with a Suz 175, but that's another story. Thanks.

 

[HighTechRedneck]

I talked to Yamaha Customer service and they told me that they will actually run longer when their run hard. I troll with my motor a lot and he said at the end of the day I have to run the boat full out for 15 minutes to get the carbon buildup out.

HTR

 

[Sea-Vu-Play]

What is the max rpm

I run my 210 around 5K. I'm pushing it with a honda 150 4S and a solas SS 4 blade, 14 1/8 X 19. I only get around 35 mph @ 5.4K wot. I had a 3 blade, 14 1/4 X 17 and the RPMs were 6.4K at the same speed and I still wasn't wot. I'm thinking I could repitch my 3 blade to a 19 to bring down the rpm and maybe increase speed. I sure like the smoother ride and handling using the 4 blade. I realy don't like to run very fast but it sure is nice if needed! I think 40 mph @ 6K would be nice.

 

[cmarkphillips]

Hi Ken,

Thanks for sharing your info. There is something wrong or not optimized with your setup. I run a Honda BF130 on a 210 with a powertech 4 bladed SS prop with 13" pitch (RXB4R13.25x13) and this prop has very little cup. At 5800 rpm, per gps, it will run 32-33 mph. There was no wind and I was carrying roughly 50 gallons of fuel and just me aboard. This is running with a t-top too.

I would love to have a bf150. With this engine, and even a factory 3 bladed aluminum prop, I figure it should push our boats over 40 @ WOT and with full fuel and 2 people on board. As a point of reference, a Suzuki DF140 will run around 37 with 1/2 fuel and 2 people, per Suzuki's performance sats. The BF150 is a more powerful engine and should easily add at least 4-5 mph to the Suz's top speed.

I wonder if you have barnacles or something growing on your hull? You should definitely be able to go faster at WOT. Anyway, I calculate with your 19 pitch prop and using two conservative prop slip factors that you should be running approx. 33.5 (20% prop slip) to 35.5 (15% prop slip) at 5000 rpm.

I suspect that you could be running faster and more efficiently, unless of course, you are carrying around a max load all the time.

Cheers,
Mark

 

[Sea-Vu-Play]

Rpm

Hi Mark & thanks

If you calculated 33 to 35 @ 5000, is 35 @5400 too far out of line? This is my first boat so I don't know what to expect. Those numbers were with about 40 gallons of fuel, two people, approx 380 lbs, T-top, electronic box and fishing gear. I trailer my boat so the bottom is clean. I did notice my tach reads almost a division and a half high @ zero which is close to 300 rpm. When I went to 4 blades do you think going to a 19 pitch was too far? It sure brought the RPMs lower than I expected. I look forward to any comments and suggestions from you or anyone Mark. Thanks again

Ken

 

[cmarkphillips]

Hi Ken,

If your tach is reading 300 rpm fast at idle, then I wouldn't be surprised when it indicates 5400 rpm if you are actually turning closer to 5100 rpm or less, which seems in line with your indicated top speed of 35.

The formulas to calculate the theoretical top speed (excluding water/air resistance, environmental factors, etc.) are:

RPM / gear ratio x prop pitch / 12, which will give you the number of feet traveled at any given rpm (remember this is a theoretical number [not a real world number], it is helpful when trying to gauge what the theoretical top end might be). Then take this number and divide by 5280 to give you the number of miles traveled. Then take the number of miles traveled and multiply by 60 to give your theoretical max speed in mph.

Ex. 5,000 rpm / 2.14 (Honda BF 150 gear ratio) = 2,336.45
2336.45 * 19 (prop pitch in inches) = 44,392.55 / 12 (to convert to feet) = 3,699.38 ft/min
3,699.38 / 5280 (ft/mile) x 60 (min/hr) = 42.04 mph

With a 15% prop slip factor, your actual speed is more like 35-36 mph (42.04 x .85).

It sounds to me like you are way over pitched, especially using a 4 bladed prop (you typically run less pitch when going from a 3 bladed to 4 bladed prop). Hooked on the Bay is a Triumph dealer on the east coast that sells a lot of Triumph boats powered with Honda engines. You may wish to give them a call – Wayne is a fun guy to talk with. I also found Merritt Marine and Powertech (props) to be knowledgeable. You definitely want to talk with someone that is both knowledgeable about propping a BF150 and our boat type.

If I had to guess, to be able to turn the max rated rpm, I wouldn't be surprised if your optimal prop was a 16 or 17 inch 3 bladed prop or a 14 or 15 inch 4 bladed prop.

While I ended up purchasing a stainless 4 bladed prop, if I had it to do all over again, I would have not bothered to change out the original 3 bladed aluminum prop from the dealership (Hooked on the Bay) as it worked just fine.

Good luck with your prop search.

Mark

PS You may wish to look into getting Honda gauges or getting the fuel use data from the engine ported into your electronics if they support this functionality. This may help you keep from running out of fuel (if you know your fuel burn rate/gallons used and keep track of how much you filled up with at the pump) as well as provide you with other interesting information.

 

[Sea-Vu-Play]

Max rpm

Mark thanks very much. I got my boat last year and it had a 3 blade, 17 on it. When I noted the RPMs were climbing way above max rated of 6000 ( I didn't notice the gauge had that offset) I asked Triumph customer service which prop was correct for my boat. I was told between a 19 and 21. Since I wanted to try a 4 bladed prop I went with the lower pitch. Oh well live and learn! OR NOT ! Being a retired metrology tech. I should have done the math myself. I installed a flo-scan fuel meter and thought about the Honda gauges.

Just for fun I was thinking of coupling an o-scope / frquency counter around one of the ignition leads and checking the accuracy of the RPM gauge.

bty what part of MD you located? I was born in Laurel. Have family around Bethesday and Savage.

Ken

 

[cmarkphillips]

Hi Ken,

I wish someone would have said to me to run some calculations before I started my prop search. I am a new 210 owner also, I purchased my boat earlier this year, so I am learning as I am going along too. After running the numbers, what I realized was that what I really wanted was a more powerful engine and that no prop was going to get me the performance numbers I was seeking (to cruise in the low 30's around 4500 rpm, and a top speed in the mid to upper 40's). While there are a lot of blogs/posts written on the internet about this subject, I have not found many that provide much useful information. The best information I have found are people that post real data with the prop specs they are running and also performance test bulletins from the manufacturers. I digress, the numbers don't lie in that they should paint a more realistic picture of what kind of performance gains you can expect, or not expect, whichever the case may be.

I wouldn't be surprised if you found that your old 17" pitch 3 bladed prop gave you the best all around performance. I don't know if it is too late to exchange your 4 bladed prop for a smaller pitch size like a 15". I wouldn't delay in finding out as I think I had 30 days for an exchange on my prop. You may also find it interesting to call Wayne at Hooked on the Bay (google them) and see what he recommends. I know they power their entire line of Triumphs with Hondas so if anyone would know, he would.

What I like about my 4 bladed prop is it seems to run with less vibration, compared to the 3 bladed props I have tested, and it has no problem getting me onto plane with 6 adults and 4 children and 60+ gallons of fuel on board. Also I get a prop slip factor of approximately 8% (under ideal sea conditions), so it's running about as efficiently as I can expect any prop to run. The trade off is that it is a 13" pitch so I won't be winning any speed races.

I installed a floscan gauge, the 7000 series which also has a digital tach, not to long after purchasing the boat. My Faria tach that came with the boat never read above 2k rpm and my local dealer didn't have anything good to say about them, so I replaced it with the Floscan. I would definitely get a good accurate tach and retest the 17 pitch 3 bladed prop. I think an accurate tach is a necessity when prop testing.

I live in Potomac and boat near St. Michaels, MD.

The Honda 150 is a sweet engine. I don't know which to be more envious of, you being retired or your 150 .

Sincerely,
Mark

If anyone is running their Triumphs hard - I would love to know what type of engine you're running, what rpms you're running at, how many hours you have on your engines, and how your engines are holding up. If you're not running your engines particularly hard and want to share your info, that's fine too. Thanks.

 

[BeeReel]

I've now have about 270 hrs on my 150HP Suzuki on a 215C TE. When making the runs to the fishing grounds (10-20 miles each way), weather permitting, generally run at just under 5000 RPM and 33-34 MPH. Fuel burn rate is optimal here at about 10 GPH. I don't find it worth running higher RPM since fuel burn rate goes through the roof.

 

[Sea-Vu-Play]

Good info BeeReel. 34 mph @ 5K with a burn rate of 10 GPH. That's good reference info. What prop are u using? I'm going to put my 3B, 17inch back on and do some checking. Question - couldn't I have my 4B, 19 re pitched down? Mark I was thinking about a digital tach from Honda but being retired my fixed income dictates my forward speed!! Everybody is so proud of the stuff they are selling.

Thanks again

Ken

 

[BeeReel]

3 blade: 3x15x21, I'm using the Suzuki digital gauges and found the calibration to be pretty accurate.

 

[cmarkphillips]

BeeReel is running a Suzuki. You shouldn't compare props between the brands as they utilize different gear ratios, which makes a big difference in the prop pitch they run. His motor is designed to turn a 21 inch pitch where the Honda is not (not at least in our weight category). You can confirm what I have written by reviewing the performance bulletins for the Suzuki DF150 and the prop that is used as compared to the Honda BF150 and the prop that is used on similar weight and configuration boats.

I hear you about the high cost of things and it's very tempting to buy into all the marketing hype, but don't fall for it. It doesn't have to be a Honda product. You can get a good tach for $100 or less. Or just keep the tach you have and don't run it above 6k, to be on the safe side.

Before you change out the 4 bladed prop, you may want to record your fuel burn at the various rpms, i.e., 4k, 4.5k, and 5k. I bet you'll find that the 3 bladed prop burns less fuel at those rpms. If this is true, then your 4 blade was really over loading your engine. You may also want to compare your fuel burn rate numbers with some of Honda's performance bulletin numbers. You should be able to find a boat they have tested with a similar size and pitch prop, weighing pretty close to what the 210 weighs dry (2300 lbs) and running a BF150. My point is that the fuel burn rates should be pretty close at the various rpms listed on similarly configured and designed boats. Once calibrated properly, the floscan gauge is accurate to within 2%. I'd be willing to bet that you could fairly accurately predict the rpms that you are running knowing the fuel burn rate on a similarly configured and sized boat and running a similar prop.

 

[Sea-Vu-Play]

Thanks Mark & Beereel

Yes I understand the differences. However isn't it correct to think that finding the right setup for my boat / engine should yield similar results? BeeReel I assume the 215 TE is a bit heavier than my Chaos. Mark I'm also thinking the heavier the boat the more the slippage. Right?? I'm going to talk with Wayne @ Hooked on the bay as you suggest Mark. I'm enjoying this informative discussion and messing around with the boat. Ya know, I'd like to repitch the 4Blade if I can because I (& wife) really like the smoother ride and handling of the 4B.

 

[cmarkphillips]

I see your point about similar hp yielding similar performance results. Sounds reasonable to me assuming all other things being equal.

It also sounds reasonable that increased weight would increase drag and thus affect prop slippage. I've reached about the limit of my knowledge and findings about props. Maybe someone more knowledgeable could share what they know affects prop slippage.

I don't know what the pitch options are for your prop or what the cost might be, but I'm confident if you called a reputable business that reworks props that they could assist you with these details.

All the best to you, Ken.

 

[Sea-Vu-Play]

Great Mark. I'm going to take the boat out probably tomorrow, drop some crab pots and do some rpm / fuel burn recording and just play around. Might even catch a fish or two! Thanks so much for the info.

Talk at ya later

Ken

 

[Sea-Vu-Play]

max rpm

Here is what I recorded with 1/2 tank of fuel and a light chop in the bay. The 5.4K was in the Jordan river with calm seas and wot. The best I could do with my over pitched 4 X 19.

RPM GPS GPH cal. mph (15% slip)

3000 14 4 21.4
4000 27 6 28.4
5000 31 10 35.7
5400 35 12 38.6

I talked with Hooked on the bay and they told me the correct prop for a BF150 pushing a 210 would be a 3 X 19. A local prop guy suggested if I raised my motor up a few holes I should increase rpm, speed and fuel efficiency a little with my current 4 X 19. That's my next move.

 

[BeeReel]

I had an opportunity today to open up my Suzuki 150HP on Buzzard's Bay to run at full throttle, 5600RPM, and the prop is 3 blade: 3x15x21. Fine tuning the trim I got the boat to just over 40MPH (GPS reading, 46+ with 15% slip). Estimate about 45 gals gas in tanks, 2 people (maybe 425lbs). I recently screwed up the calibration on the fuel flow so no numbers but likely 14-15+ GPH. Haven't yet figured out how to reset calibration on the Suzuki gauges.