BF130 and old Merc prop

[maillon]

Hey Guys,<br /><br />I winterized my 2000 BF130 the other day. While I was at it, I greased the prop. Prior to putting on the prop, I compared it to an old (70s-80s) Merc prop. Both props have the same diameter. My honda at WOT is 5200 with a 19 pitch. I'd like to try a 17 pitch. The Merc prop is 17 Pitch. Just for yucks, I sized up the old Merc prop with the Honda prop and though there are some differences, it seems that the Merc prop would work. I slipped it on my Honda's shaft and appeared to fit perfectly. <br /><br />Do you guys think I could cause any harm if I were to use this prop?<br /><br />Thnaks

 

[MajBach]

Re: BF130 and old Merc prop

I have a honda 19" prop and a Merc 17" cupped prop for my Honda 90. You need an adapter for the Merc and a different thrust washer. <br />Surprisingly, very little difference in performance between the two. Merc gets slightly better hole shot and tops out at 5600 rpm at 37 mph. Honda prop cruises nicer and tops out at 39 mph at 5400-5500 rpm. A cold day makes more of a difference on performance than switching props.<br />One thing I do notice that I cannot figure out why is that even though the hole shot is better with the Merc prop, the motor typically dies (like fuel starvation) when I gun it from a stop. I really have to ease into the throttle with it. It's most apparent on light loads, almost like the motor cant keep up with how fast the throttle wants to push it. I am wondering if the adapter sleeve for the Merc prop restricts the through exhaust flow to much. You probably wouldn't hvae this problem though being that your motor is FI.

 

[SaskLund]

Re: BF130 and old Merc prop

Maj, what type of boat do you have with your Honda 90?

 

[SaskLund]

Re: BF130 and old Merc prop

Maj, I have a 1999 Lund 1900 Pro V tiller and a 99 Honda 90 Hp (am converting to remote steering this winter) I have tow props that came with it. One seems to spin out on take off and revs 6150 WOT which is redline. I also have a michigan SS prop 13x17 that I have not tried out. Cannot read pitch on aluminum michigan prop. Will the stainless even if same pitch etc. take me out of redline. What prop do you suggest for this set up?

 

[Hawaiian]

Re: BF130 and old Merc prop

Sasklund, are you sure redline for your motor is 6150 rpm? My 2002 Honda 90 manual says that full throttle operation range is 5000 to 6000 rpm.

 

[MajBach]

Re: BF130 and old Merc prop

Sask: <br />I have 17' Sylan DC aluminum. Typically it is heavily loaded with gear and it is a wide hull comparatively at almost 8' with a gull wing profile (i.e, not flat bottom but more like a semi-V). I also have a Dolphin on the cavitation plate and the motor is mounted one notch above lowest position in the water. I am actually a little disappointed at it's top end but I suppose it is for the better as it starts to ride a little 'wishy-washy' at 38 mph and up. I have tried performance comparisons with and without the Dol-phin and it only adds to performance. Top end unaffected, hole shot greatly improved - espescially under heavy loads, and ventilation almost non exsistant. I have also tried the motor on its lowest position in the water. In this configuration, top end drops at least 5 - 10%, bow lift is excessive and believe it or not, ventilation is worse. Next year I will try lifting the motor a notch.<br />I have four props, all aluminum: 15" honda, 17" Merc, 17" Honda and 19" Honda. With the 15", I too top out at 6150 and I also get the highest speed: 40.5 mph. But it is too high for everyday cruising. However, hole shot is neck-snapping, on the plane in less than a boat length.<br />When I first got the boat, I tried different props (the ones above). First day out I hit two rocks (different props). Second trip out, hit another quite badly - broke skeg and needed to replace shaft. Third trip out, boat almost sank after sitting in water for a week. Turned out to be a leaky pitot tube. And fourth trip I again nicked a small rock. Hence, I 'bought' all these props. What really sucks about the entire story is I have been boating in this area for 10 years and never came close to hitting a rock. Go figure, it was a crappy old boat and really old motor. I get the new one and sh*t happens. The one rock I hit that did all the damage was actually uncharted. Because it never broke the surface of the water, they wouldn't let me name it when the Notmar was released. BTW, this is east Georgian Bay - hazardous to say the least.<br />Anyway, the point of all this was that they managed to fix all of the props, even the one that lost a complete blade. I dont have too much confidence in 'fixed' props. As long as they're balanced, they're OK to run but I don't believe they ever match original performance. I arrive at this conclusion based on I book I read about props many years ago. Unfortuantley, I do not remember the name of the book but it was good reading. You'd be surprised how a quick slip through a sand bar can have NO noticeable affect on your top end but reduce your fuel efficiency by 30% simply becasue it bent the prop a hair.<br /><br />If you are spinning out with your aluminum prop, I would first determine if it is the prop hub spinning (I don't even know i this prop will do this) or if it is ventilation (might even be cavitation if it is a really fine pitch). Cavitation should produce noticeable pitting on the prop blades though. It's far rarer than most people think. <br />Is the aluminum a bigger diameter than the SS? Do you know what speed you are achieving at 6150 rpm? Is this speedo, paddlewheel or GPS? I would expect your boat is heavier than mine and thus the aluminum is at least 15", maybe even 14". I would defiantely think the SS is a better choice.<br />BTW, WOT range is 5000-6000 as suggested already. Redline is 6500 and I believe there is a limiter. I try and have mine peak at 5400 rpm where max hp is achieved. I don't use a SS prop (would LOVE to try one) because of all the rocks where I boat.<br />Do you know what the weight is of your boat? Now that I think of it, your boat might even be lighter than mine, despite its length. Perhaps the aluminum you are running is 17" already. If so, putting on the stainless will make matters worse.<br />There are far better prop experts here than myself (I am no expert anyway). The fact that I own the same motor as you doesn't matter a terd when i comes to prop knowledge. But I would enjoy hearing back from you. Why not just try the prop? I change props like I change clothes. Doesn't hurt. And I never buy a prop without trying it first (or damaging it). I don't know of a marina that wont let you try a prop. Mine doesn't even as for a deposit.<br />Geeze - it must be cold as heck out there by now. You still out in the boat?

 

[SaskLund]

Re: BF130 and old Merc prop

Thanks for the replies guys! Dam rights it is cold out here.....below freezing in the evening and about 4-40 degrees celsius in the day.....and I just got the boat and only got it out twice. I have to go to Regina this weekend so will not get to try the ss prop out. Actually took the boat into the marine shop here to get my tiller converted to remote..I have a console already. I am rather green at all of this. My Honda tach shows anything over 6000 at redline so I assumed anything over this was redline. I am not sure what my aluminum pitch etc is as it is not on it. I emailed michigan with the ser# to find out. Sounds like your boat hauls a#$! hope mine goes over 32 with the other prop. I am also not sure of the boat weight. I will get this all figured out soon and will let you know. <br />Boy you had some bad rock luck...that scares me as well! This was the reason I did not go out with the ss prop the first two times. <br />Keep in touch!

 

[Hawaiian]

Re: BF130 and old Merc prop

I spoke to the mechanic at the local Honda dealership today. He told me that redline (maximum rpm motor should operate at) is 6000 rpm. He also said that the rev limiter kicks in at 6500 rpm and running the motor at short bursts of up to 6200 rpm should not harm the engine. My 90 hp sits on a 1500 lb dry weight Boston Whaler 16' Dauntless. It has a deep "V" and is rather heavy. With a 13.75 X 15 pitch Solas stainless prop, it will go 38 mph at 6150 rpm. I have the motor up 2 holes so the anti-ventilation plate is almost 2" above bottom of the hull. The prop only ventilates in rough seas. I also have a new 13.25" X 16 pitch Honda performance stainless prop, it is double cupped which makes it more like a 17 pitch. It will take the boat to 40 mph at 6000 rpm but the hole shot suffers a little so I'm going to put it on e-bay and sell it.

 

[MajBach]

Re: BF130 and old Merc prop

Perry:<br />That is some interesting data. I am surprised at the weight of your boat. friend of mine has a 17.5' Wahoo (like a Whaler). I was surprised that his boat weighs less than mine. mind you the beam is a fair bit narrower. My boat's length to width is almost 2:1; I am sure that has an impact on performance. But with your boat being 1500 but getting better performance than mine? Wow!. Then again, Whalers are known for their hull design. I'm sure having no rivets and SS props makes a difference too. Even though my boat is 950 dry weight, with motor and seats, equip and batteries etc, I guesstimate it is around 1350.Add the outboard, another 370. Me and gas yet another 350. Pushing a ton.<br />I suppose then our boats are pretty similiar in weight and performance when i look on it again. Although I am sure you can pound the waves much better. I spent many a day in my friends Wahoo and wouldn't even consider putting my boat through the same rough conditions. His boat falls just short of 50 mph with a 100 Merc on it.<br />How do you measure speed on your boat? I use a GPS. I had a pitot on the boat and then switched over to the built in one on the outboard. Both read the same: about 43 mph when my gps read 38. My paddle wheel on the sonar reads 10% high when on the plane, but has a manual correction on it. Don't know why I am hung up on the speed thingy, I rarely drive over 30 mph. I remember my 18hp 'Rude pushed my 14' aluminum to about 22 mph. Then again, I could fit two of those old boats inside the one I have now. When I was shopping for a 16 -17' new boat, I figured 40 hp would be great, all thats needed. I was advised no less than 70. Ended up with the 90 because of a good deal. I was told though by a few 'experts' in the business that the boat should do around mid to high 40s, so I guess I am a little disappointed still. Although, many people who comment on the boat see this huge motor on the back and ask me what it's like to do mach 1. LOL.<br />One more thing, having the motor up that high, you said you have no ventilation. Are you running a stingray or the like?

 

[Hawaiian]

Re: BF130 and old Merc prop

MajBach, when I was at Crow Lake this summer, I rode in a friends aluminum boat and yes, the rivets seem to rob you of a couple mph. My boat has a 7' beam and with 45 gallons of fuel, ice, gear, 375 lb motor and me, the weight is over 2500 lbs. When I raised my motor 2 holes, it was amazing how the performance improved. I have no fin on the anti-vent plate. The stainless prop is what keeps it from ventilating because it has more cupping than an aluminium. I measure speed via Garmin GPS though top speed is not really that important to me because here in Hawaii, the ocean gets rough and there are few places where I can really open her up. The deep "V" really helps the boat handle well in big waves.<br /><br />You say you try to have your motor peak at 5400 rpm. What size (diameter and pitch) prop are you using? You put less strain on a motor when it is propped to reach max rpm (6k) with an average load because of better acceleration and the fact that you don't have to run at WOT all the time.<br /><br />How high is your anti-ventilation plate in relation to the bottom of your hull? Have you ever looked at your Dolphin fin while cruising at full plane? Is it above the surface of the water? If your motor is too low it will cause drag and thus reduce top speed.

 

[rodbolt]

Re: BF130 and old Merc prop

Hello <br /> to answer Mailon's original question, yes the older inline 6 and the 80 hp and up inline four props will fit the honda. merc made all the lower units for the larger hondas. if you pull the prop shft you will find merc numbers on it . if you have a torque flow hubbed prop you will possibly need a merc kit but all the Honda's at our marina use merc wheels because the Honda selection is very limited and very expensive. price the difference in buying a aftermarket merc wheel vs a Honda wheel good luck and keep posting

 

[Hawaiian]

Re: BF130 and old Merc prop

Rod, do you know when Honda started making their own lower units? I don't think a Merc prop would fit on my shaft.

 

[MajBach]

Re: BF130 and old Merc prop

Perry:<br /><br />Don't know what size dia my prop is - whatever the standard was with the motor. I would like to play around with props of the same pitch and different dia. to see how they differ.<br />I find it difficult to estimate where the cavitation plate is supposed to line up with the hull because of the "V" shape of it. but yes, I have looked and my Dolphin probably sits in the water an inch while planing. curiously, it has had no effect on top end. But, after reading other posts here that state the real benefit of a fin is to allow to raise the motor height, I will experiment with higher positions. My biggest concern is the directional stabilty that is lost at higher end with the motor out of the water more.<br />I do agree with you as well about having the motor peak out at 5400. Just like some of the pistion planes I flew, it bogs the engine to some degree with to high a manifold pressure. Kinda like trying to bike up a hill in tenth gear. However, WOT range IS 5000-6000 to I am not breaking any laws. I prefer it this way as it means that at cruise with the 19" prop, I am turning 4000 rather than 4600 on a finer pitch. You can't even hear me coming. I don't see your point though about not having to drive around at WOT all the time. WOT is WOT regardless of pitch. Speed at WOT should be roughly the same, regardless of prop - unless you go to extremes. The rpm changes and personally, I would rather run WOT at a lower rpm if possible. If I achieve the same speed at WOT at a lower rpm, I am not lugging the engine at that point. Not only that, but if you achieve WOT at the peak hp, you're doing the engine better than if you were to go higher rpm at a lower hp.<br /><br />I'm pretty sure Honda made their own lower units in 2001 or 2002.<br />Would like to know more of what a torque flow hub is or whatever and if this is related to my engine quitting. Is ther a solution?

 

[Hawaiian]

Re: BF130 and old Merc prop

MajBach, if your hole shot is good with the 19 pitch prop, you don't need to run at WOT very often. If I had that prop on my boat, I'd be at WOT all the time, my fuel consumption would suffer and my motor wouldn't last very long. My boat is heavy so I NEED to prop it so it reaches at least 6000 rpm with an average load. On the Boston Whaler forum that I frequent, it is a rule of thumb to prop your boat to reach at or near max rpm.<br /><br />I bet if you raise your motor one more hole, you would gain a 100 rpm where max hp is produced and a little more speed on the top end. As long as the Dolphin fin sits on the surface, it will provide stability. If it is under water, it is causing drag.

 

[rodbolt]

Re: BF130 and old Merc prop

Hello<br /> not sure about when or if Honda started making there own gearcases I have a 2oo2 75 in the drystack that still has the merc case. and the torque flow prop is another dang engineering thing that went horribly wrong and now the customers will pay and pay and pay. but like the stator problem merc will never ever admit it.the hub system is where the same wheel can be placed on many different motors with just a change in the plastic hub kit. the only problem is that you have to keep the hub torqued to 55 ft pounds and if anything over 150 HP they crack and break up. I just replaced 2 today on a 26 jupiter with twin 200 HPDI yams. did it 120 hours ago as well. good luck and keep posting

 

[MajBach]

Re: BF130 and old Merc prop

I still dont understand what a torque flow hub is. why was it designed? to make props interchangeable? My merc prop fits on my honda withouy the need for any plastic kit. However. there is a brass sleeve that is inserted over the drive spline before putting the prop on. I was wondering if this sleeve contricts the exhaust gas flow causing my motor to die under heavy acceleration.

 

[rodbolt]

Re: BF130 and old Merc prop

Hello. the torque flow hub was designed so that the props could imterchange with other manufactures motors by simply changing the hub kit. if the brass sleeve you are refering to is like a large thick washer that goes on fwd of the prop then it is called a thrust washer. the thrust washer transmits all the fwd thrust made by the propellor to the propeller shaft. your honda prop has one as well. I have never seen one so large as to stall the motor. if the prop is way to big it may stall the engine.would be like placing a manual shift car in high gear and floorboarding it from a standing start.

 

[MajBach]

Re: BF130 and old Merc prop

Rod:<br />I have a special thrustwasher for my merc prop that differs from the HOnda one. However, there is also a brass sleeve that fits over the driveshaft. The prop goes in first then the sleeve is inserted though the center of the prop. It has slpines both inside and out. The rearward most part of this sleeve has a large slip that catches the prop hub so as to keep it from sliding in further.

 

[maillon]

Re: BF130 and old Merc prop

MajBach,<br /><br />Why do I need a different thrust washer? The old merc prop slides completely over the splines and the back of the prop goes up against the thrust washer It seems to fit perfectly.<br />- Mike

 

[MajBach]

Re: BF130 and old Merc prop

I don't know if you do for certain. But on mine, there is a suttle difference on the inner lip diameter. Going from one prop to another, it's hard to notice you need a different washer. But going the other way, it's obvious as the thrust washer wont fit.