looking for wallyehead

[Jim Thacker]

I am the guy who was asking about Pirhana prop overheating. One of you guys said they would look up some numbers and see what I need in the way of a prop. Now I apologize if I am being to forward here as I have no idea how long something like that would take but do you have any info about what I need to do.

I just came back form my c abin and hereare some new info. The pirahana prop I have is a 12 5/8 X 21XB whatever that means......

very heavy load........way over capacity but it is a 1776Prov V Lund so it can take a lot of weight.....
3700 rpm 10mph......could not get up.....:'(

so stopped and puton a regular 15 pitch prop........... 6200 rpm and 27mpho

Heavy load barley got up after a long time........ 5200 rpm 30mph :/

2 in the boat 5600 rpm 35mphd

It may be that this is all I should expect from a 90 hp Honda........... I know my 2 stroke 90 Yamaha was clearly better and would always get up no matter what but that was 2 stroke and this is 4 stroke>o

 

[Dhadley]

Re: looking for wallyehead

"It may be that this is all I should expect from a 90 hp Honda........... I know my 2 stroke 90 Yamaha was clearly better and would always get up no matter what but that was 2 stroke and this is 4 stroke"

Very typical comment when folks go from a 2 stroke to a 4 stroke especially when loads change dramatically from light to heavy. Changing props for the heavy load is a good idea. Glad you had one with you.

 

[Crownie2]

Re: looking for wallyehead

It could be the prop. Perhaps the 15" pitch is not far off but did you notice that the Honda 15" prop is 13.5" in diameter?

IMO that increased diameter would help a lot.

Let's see what Walleyhead says...

Bob

 

[walleyehed]

Re: looking for wallyehead

Sorry if I left you hanging...sometimes duty calls and I forget where I left-off.
I have a special place for the Pirahana's I've ran.....on the shelf right next to my Ballistics.
One thing I've also learned (the hard way), is the 4-strokes don't give as much room for leaning too far one way or the other and Dhadley said it in better words..."this is a common response..."
I do agree with Crownie on the diameter issue..the larger one should be best for hole-shot/loads, and in your case, I'm not sure that maybe a 4-bld SS may be the best bet if all you want is one prop.
I don't know if Solas builds a stainless for the 90 in 4-bld, but they do build a 4-bld aluminum in 13 pitch that could be worked to act like a 14P which might be an option. It would increase your load carrying ability, but likely drop some speed.
In the playing I've done with some of the new transplant Suzuki's here(4-strokes), it takes about 1.3 times more HP to carry the same load at intermediate speeds...top-end doesn't seem to be a problem but hole-shot and mid-range suffers.
You "may" have to go with a 13P when loaded and stay with the 15 with just a couple on board. Wish I had a better answer for ya...

 

[Jim Thacker]

Re: looking for wallyehead

I appreciate the help.....As a glutton for punishment I just may take a long look at the new honda coming out. The stuff below was sent to me by a friend who saw this in one of their magazines they subscribe to. It sounds like the lower end torque might fix the problem ....Just the 50 pounds less on the transom has to help a lot d

New Honda 75-hp and 90-hp Outboards Introduced 10/5/06
Honda Marine announced last week the introduction of two new outboard engines – a 75-hp and a 90-hp – that might send chills up the spine of their competition.

First, at 359 lbs. it is the lightest 4-stroke in its horsepower range, as much as 44 pounds lighter than at least one 4-stroke in its class.

Second, Honda has what they call “BLAST” -- for Boosted Low Speed Torque – which advances the ignition timing from a standing start with pedal-to-the metal that results in explosive hole shots.

Third, this 1.5 liter, 16 valve, in-line four cylinder engine is the same engine used in Honda Motor’s best-selling car, the FIT – so it promises to be the most reliable outboard on the market. The engine has been put through more testing and actual use than virtually any outboard on the market, except Honda’s own 225-hp engine that is also a light truck engine. This is a big reason why Honda has won the JD Power and Associates award for customer satisfaction the last two years running.

There are a number of other innovations that Honda Marine has built into the engine including an oxygen sensor that adjusts the air/fuel mixture to speed and load while maximizing the power and fuel economy between 2000 and 4000 rpms, a three way cooling system that the company says keeps the head cooler than the block for reduced engine wear, and their VTEC™ system which engages a high output cam lobe at high rpm for greater high-end performance.

Both the new 75-hp and 90-hp units have 44 amp alternators which provides 35 amps to the battery, according to Honda, along with a patented multi-layer paint process to fight off saltwater corrosion.

Both products deliver virtually smoke-free performance (we saw no smoke at all during a day of testing) and meet California Air Resource Board (CARB) 3-Star requirements, which are 20 percent lower than those federally mandated by the EPA.

The BF90 and BF75 boast an Engine Alert System that uses visual, audio and rpm reduction circuits to alert the operator of conditions which contribute to engine damage, such as overheating, low oil pressure and over-revving. So, no matter how blind or hard-of-hearing you may be, these instruments are going to get the message through to you that something is wrong and you had better shut the engine down.

By the way, those little chips in the Honda engine – and most other brands, too – will record how you ran the equipment. So the days of trying to pull one over on the warrantee mechanic are over.

The Honda BF90 engine is available in both 25-inch and 20-inch shaft models, while the BF75 comes in a 20-inch shaft length.

Honda says that it has built over 20 million engines over the years for all sorts of applications including cars, trucks, ATVs, Indy cars, and PWC's in addition to their outboards.

o

 

[Crownie2]

Re: looking for wallyehead

Yes - this promises to be the latest and greatest (midsize) from Honda. It would be a pitty to repower and spend all that money, though...

A new prop or even two would be cheaper!:devil:

Bob