North Australian FISH FINDER TM forums

littlemack3 wrote:And are you using gps to check speed or just reading the engine gauge not familar with honda but if anything like merc the readout from the engine never reads accurate reads anywhere from 5 to 10 ks slower when going flat out depending on conditions

Yeah I'm using the GPS speed. The Honda gauge reads quicker but yeah GPS Is most likely more accurate.
My old man told me to ring the ETEC/Honda dealer in Cannonvale who we bought 3 ETEC's through as they are also the quintrex dealer and have done heaps. I'll ring him tomorrow and see if they have a magic prop size that does the job!

qiksix wrote:This has actually got me interested, ive just done some calcs on my larger boat to work out prop slip. Turns out dannett is about right. Ive got a 26ft glass boat with a 350 mercruiser with a bravo 3 sterndive with twin duo props. Full noise at 5000rpm I get roughly 70kph. The calculations actually give me a speed of 92kph. That's about 20% prop slip at full noise.

Your boat no doubt being heavier than my bare tinny makes me believe that you could be getting a bit more slippage than myself. Another good indicator is the fact you dropped 300rpm with a 13p prop. I reckon your little 50hp is using all of its 50hp to do what it is now, it's on it's limit.

Yeah but doesn't explain how my mate (who's prop I borrowed) running a 50hp Yamaha four stroke on a 435 hornet trophy tiller steer which is close to same seating position as where I sit in my side console. His GPS is giving him close to or on 60km/h.

I've made sure there is no water in the hull and I've only got safety gear, anchor, 3 seats and the console. The bare hull weighs is only 317kg so let's say 500kg with motor and fuel so it should be moving along better then it is.

With the review which you can view on boatsales it says they got 60km/h @ 5200rpm with the 60hp Yamaha. Honda say full throttle is 6000rpm so I should be achieving better then what I am. Stupid Honda heap of cr.p!! Need an ETEC

I reckon my hull would be under 100kg. It would be interesting to see how much the 435 hornet weighs. The Yamaha could have different ratios in the box too. How many rpms was the yammy doing on the 435 hornet to get near 60kmph?

What year is your motor from memory honda are a less powerful motor compared to a yammy im 95% sure you would have to check im sure it was bottom of list on comparisons a year or 2 ago it was one of the lighter ones like Suzuki but was close to 100cc less or there abouts compared to a yammy not 100% sure would have to find that print out I had when I was looking to upsize mine

It's a tiller but full throttle. Guessing 5200rpm. Was reading an article on western angler which said Honda 50hp have a genetic manufacturing fault in them which causes them to lack power and cavitates and blokes on there said they needed to go to a 4 blade prop to eliminate the cavitation issue, they said 28-31kts (51-57km/h) full stick on vee hull boats.

littlemack3 wrote:What year is your motor from memory honda are a less powerful motor compared to a yammy im 95% sure you would have to check im sure it was bottom of list on comparisons a year or 2 ago it was one of the lighter ones like Suzuki but was close to 100cc less or there abouts compared to a yammy not 100% sure would have to find that print out I had when I was looking to upsize mine

It's a 2007 model, makes sense what your saying

Just had quick flick on brochures current models
Yammy 50 4 cylinder
996 cc

Honda 50 3 cyclinder
808 cc
50hp at 6000rpm
103 kgs

The yammy would defiantly have more torque with more cubes, that's something everyone forgets about and it could make all the difference depending on ratios.

yeah but you'd think they would counter act that with higher gears and a different prop pitch

50 hp is 50 hp regardless of engine displacement. True a larger displacement would generally yield a greater torque output but given that you are reaching 6500 rpm that is not the issue here, though it may be a contributor to the less than ideal planning speed. Given this it is unlikely that there are any performance issues with the power head otherwise you wouldn't be achieving 6500 rpm.

It is probably worth getting your prop checked and tuned by a professional, I had a 17 inch Yamaha prop when measured was delivering just shy of 17 inches and a Solas 19 inch that was just shy of 18 inches. Obviously that will affect top speed performance but more notably the pitch between each blade of the prop varied by up to almost an inch which cause cavitation and reduce all round performance. Marcus at Northern Propeller Service tuned both and was able to stretch the 17 out to 17.25 inches and the 19 up to 18.5, the resulting performance difference on the water was quite noticeable. Such a tune should be about 1/3 to 1/2 the cost of a new prop (smaller props will cost proportionately more).

As for the boat, as suggested earlier raising the outboard one or two holes may improve performance as well. Experiment with weight distribution in the boat, if I want to run fast I throw my deckie and esky and as much tackle and weight as I can on as far forward as I can. The boat gets noticeably nose heavy with it's tail sitting high in the water, but it's good for around 6 km/h in good conditions. Also you may want to change to a performance prop with a bit more rake in it to help raise the nose of the boat. Don't expect any one thing will make all the difference, rather you will find 3 to 4 km/h improvement in each adjustment but together you may find 10 to 15 km/h.

Dan

Yeah well I can't move to much around because it's all under the floor in the storage areas, obviously quintrex put the storage areas in where they are for a reason. In the back is the battery, isolator, live well. Centre is the console, 2 seats and 50L esky. Front has 1 seat for casting, safety gear, tackle trays, tackle box of with spanners and spares with the anchor up front. Pretty basic really. Maybe that 60hp ETEC is looking better and better each day haha

There is the possibility that your mates Yammy 50 is actually a 60....(50 with restrictor plate removed)..........I did it with mine and it does make a difference......that's a 17% hp increase.......better ask him if he cooked the books so to speak.

And please don't mention E- testicle outboards again.

Na spoke to him today and he said it's just a 50hp. Also I have no idea why no one likes ETEC's..... Maybe they just can't handle the horsepower of a injected 2 banger haha also I know up north the dealer isn't the best

Spoke to the quintrex Honda dealer and they said unless the dealer moved the fuel tank forward against the casting deck the weight distribution is all towards the back and causes the issue. An inherent fault with hornet trophies apparently. They said basically that's all I'll get out of the 50hp due to the weight.

Bottom Bashing Bloke wrote:Yeah well I can't move to much around because it's all under the floor in the storage areas, obviously quintrex put the storage areas in where they are for a reason. In the back is the battery, isolator, live well. Centre is the console, 2 seats and 50L esky. Front has 1 seat for casting, safety gear, tackle trays, tackle box of with spanners and spares with the anchor up front. Pretty basic really.

You may need it further back to get the nose out of the water, my point is try a few things and get a feel of how it changes the boats performance.

Bottom Bashing Bloke wrote:Maybe that 60hp ETEC is looking better and better each day haha

Well at the moment you're not getting the full potential out of the 50hp Honda so that's an expensive new prop!