59ci Merc help please SRG, Foreman, MWhite ETC.

Looking to speak with someone about setting up my boat. 14x48 Rhino flat bottom, 50hp Merc tiller. No one in my neck of the woods is doing anything like this. I've been reading for months now online and can't get nearly as much info on these Merc's as there is on the Yamaha's.

Engine is 2006 59ci Merc 50hp. Bone stock right now. 13p factory prop.

What prop would you fellas recommend? Thru hub looks like about 17" pitch is all I can find on a 13 spline. Figured that will be the prop I use when going out with my woman and dogs to just cruise.

Seems like the Mercury 18p Chopper is pretty popular and over the hub exhaust for go fast days.


Ok, heres the kicker, I have a long shaft engine. It's on a Vance jack plate and I'm gonna have it pretty high, but nothing like you guy's with Bob's nose cone and low water pickups. So that will play into prop selection I would think. I should be able to get the cav plate up higher than the hull bottom so I hope that will be sufficient. Otherwise, I'm gonna have to buy a tall transom boat for my long shaft. Guessing the reason a 40 Merc is what all these guys run is because they are short shaft. I pretty much stole this engine so I'm going to work with it for now.

Not some dreamer that expects to just bolt it up and do 75mph either. I will put in the work, testing and money to do what's needed. Just need someone to help me that has experience. I know most racers won't share secrets and I don't expect to hear it all, but I'm on a lonely little stretch of river and most of the time I don't see anyone else much less race. Just trying to get out here and get my speed fix on the weekends.

I've tried pretty hard to get in touch with the fellas listed in the title. Looks like after about 2015 these flat bottom race boats might have kinda died out and people may have moved on. If someone could put me and them in contact together I'd owe ya big time. I appreciate all the help!

Just ordered a 19p Black Max prop that I found real cheap on ebay. Figure that will let me see how the boat is going to act between 40 and 50mph. Sure wish I could find someone with some knowledge on this.

What hp is your motor?
Can you post a pic of your boat

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Originally Posted by fs5

What hp is your motor?
Can you post a pic of your boat

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Engine is 2006 50hp. Seems to run really well. Not sure if my hull is up to it or not. I'm going to give it a shot before I buy another hull though.

I can take more pics if needed. This is all I have.

Hull is probably heavier than most in it's size. All .125" welded with only two longitudinally welded stringers inside and underneath. It's somewhere around 375 pounds (170kg).

Attachment 67655

Attachment 67656

My jack plate is now maxed out. The highest I could get the engine is with the anti-vent plate almost dead even with the bottom of the hull. I'll be looking for a tall transom hull once I'm back from vacation most likely.

You could 'paint stick' the motor higher with a strip of wood. Long as she's bolted on good it won't be a problem.

Jeff

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Originally Posted by Fastjeff57

You could 'paint stick' the motor higher with a strip of wood. Long as she's bolted on good it won't be a problem.

Jeff

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Unless I'm mistaken that be pretty hard to do with my jack plate. The clamp that goes on top of the transom doesn't really touch anything. Engine has 3 heights for the 4 holes and they are on the highest setting. I could always drill the jack plate higher, but I think I'll just end up with another hull. I'd like to get one of those fancy 8 degree V style anyhow. The flat bottom will beat ya to death on the big lakes around here and I like to do some exploring when I'm not trying to whip up on jet skis.

..." The flat bottom will beat ya to death on the big lakes around here "

You said it! Have the same problem where I boat. After moving to MD, I intended to build a tunnel hull until I did some running around. Yikes!
Settled for building a deep vee instead!

Jeff

Yep, I guess I’m trying to have my cake and eat it too. I don’t have a second boat or ski or anything. I have my jon boat and I’d like to bust some tails on “jet ski Wednesday” and then take my girl and my Dobes out on weekends and hit the beaches and such. I’m looking at some of the newer duck boats that supposedly come on top the water like a bass boat. But anyways until then I’m going to give this little Rhino all she can handle.

I printed off the service manual and went through the basics tonight. Sync’d the carbs, checked the impeller, and swapped the pisser out for the plug up top so she will tell me the engine is being cooled. Engine only has 6 hours on her. Can’t wait to get the new prop on and see what the hull says. Pretty sure it has some nasty rocker that I won’t be able to fix. But hey, this is part of it. In the mean time I’ll keep watching SRG and Bogalusa boat club videos. Haha thanks for the help thus far fellas. Keep it coming

The 50hp have different port timing to the 60 hp. You can fit some after market reeds and remove the reed stops and run the washer style retaininer like the 60 hp. Also run the bigger carbs from 60 hp.
Rev limiter is the black wire with yellow trace goin to limiter box.

I plan on finding a set of the 60 carbs. Sure wish Mr. Danny (1995US1) still offered the 66.6hp kit with carbs and all in one package. Port timing isn't too big a deal to me because I will eventually have the thing ported out and all.

Kind of learning the engine right now and have read nearly the whole service manual haha. Seems like this engine has a lot more top end than my previous engines? When I give it a little throttle in neutral it revs up real quick like a dirt bike. Also, when at low throttle I can feel it hit a point where it comes into the powerband and starts pulling real hard. Hopefully thats just the nature of this engine. I may pull the carbs and check them out and clean them to be sure.

19p prop and new fuel tank are arriving today. Pretty anxious to see how the hull reacts. One detail I may not have mentioned is the engine is the gas assisted tilt version. No power trim, but if I hit something it will kick up rather than whatever would happen otherwise. I'm pretty positive I will end up installing a factory tilt and trim unit or possibly an aftermarket unit which would be great so I can keep the kick up feature.

I like to run several of the smaller rivers than dump into the TN river and they can get shallow with stumps and debris.

Will report back this weekend after I hit the water. Hoping to throttle through the bouncing and have enough prop to get some lift.

Couldn't seem to get up into the powerband with the 19 pitch. A little bit surprised, but might be a little heavy and low on HP to turn that much with my engine so low in the water. Going to need to find a set of 60 carbs and reed plates. Any opinions on other things I can do before taking the powerhead off for porting? Guess a lightened flywheel and reeds is about my only option.

I've also noticed some people saying they run over 6000 RPM's on these engines in stock form. I'm confused on how that's possible. I thought the biggest factor on RPM was the port height inside the cylinder. I've read of people with stock merc 50'-60's turning 6500+ with 18p propellers and I can't help but question if something is wrong with my engine. Was pretty surprised it wouldn't push my boat with the 19p.

Hope to stir up a crowd of people with knowledge on this soon. Hard to believe how many used to race and mod these engines and I can't get much info other than the old threads.

It's been awhile sense I've been on here. Bateman I don't know if I can help or not, you need to try different props, at different heights, 19p prop will need to rise your motor I order to spin it, other wise you not going to turn it, same gos with a 18p chopper prop, you got to get motor up, your boat weight has a lot to do with how it performs. R you trying to run a racing prop or a fishing prop?

Your weight and what you have in boat plays a part in how it runs, a stock motor will turn 6500 rpms, but things have to be set up right. It takes lots of testing, setting up motor, trying different props and the liter you are the better.

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Originally Posted by MWhite

It's been awhile sense I've been on here. Bateman I don't know if I can help or not, you need to try different props, at different heights, 19p prop will need to rise your motor I order to spin it, other wise you not going to turn it, same gos with a 18p chopper prop, you got to get motor up, your boat weight has a lot to do with how it performs. R you trying to run a racing prop or a fishing prop?

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Man I can't believe you caught wind of this little thread lol. Look like most of yall have been gone from here for a few years at least.

Good to hear about the motor height. I had a feeling that it was just too low in the water. I want to turn a racing prop, but not until I get a handle on all this and learn a little more. They expensive.

I think my boat weighs a bit over 350 pounds just the empty hull so she ain't light. I been keeping an eye out for other boats to put my motor on and be a little lighter.

I appreciate you coming on here to give me some pointers. I've read all the racing and smack talking threads yall had going back in the day. Wish it was still that popular haha.

I got the boat with me today. I'm gonna hit the water after work with an empty hull and see if I can drive through all the bow bouncing. Might drill some new holes in the jack plate tonight to see how high I can get the motor.

If it’s bouncing, I’d check the bottom of your hull and make sure it’s straight. It might a have a rocker built into the hull .if it has it’ll be near impossible to stop..
If it’s straight a good Hi rake stainless prop will settle it down.

I'll have to get a pic of the boat bottom. I don't think it's gonna work to well. It doesn't have a corrugated bottom like most. It has two reinforcement stringers that run long ways. 2 inside the boat and 2 up under the boat. Welded about every 6 inches. Looks like a bunch of small ripples or waves under the boat due to that.

Here is a pic to give you an idea of the boat bottom. It's just one big ole sheet of .125" with no corrugation. You can see if flexing and flopping at speed from inside the boat.
Attachment 67731


This just a pic of my main bitches enjoying the weekend with me. Have to tell them to stay off the bow deck at full throttle. They crazy lol.
Attachment 67730

Not a high speed hull--period. You might want to start looking around for something more appropriate. (Where I boat it's rough as hell, so a deep Vee is the ticket.)
Your dogs remind me of my kid's puppies.

Jeff

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Originally Posted by Fastjeff57

Not a high speed hull--period. You might want to start looking around for something more appropriate. (Where I boat it's rough as hell, so a deep Vee is the ticket.)
Your dogs remind me of my kid's puppies.

Jeff

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Yea I think you right. Prob going to go with a shallow V style jon boat. Weldbilt or similar. River don't get too rough unless the weather real bad or a holiday with bunch of boats running around and in that case we stay home. The little aluminum boat has treated me well up until trying to push it faster. Going to put it up for sale after I get back from the beach.

Well, I got the Merc running like a top after a little tinkering. Idle mix wanted a little more fuel after syncing up all the butterflies on the carbs. Then adjusted the idle timing a bit and she fires up first yank now and idles all the way through the marina. That made me pretty happy so we took it out yesterday for a bit between storms. The bottom plug is still looking dry when compared to the top cylinders so I may have more carb work to do, but it ran pretty smooth.

After all that I took two big crescent wrenches and put some real small downward bends in my "trim tabs" which is really just where the boat bottom extends out passed the transom about 3 inches. I just did about a 4 inch wide section on the very outward edges. This made a huge difference. I might have lost 1 mph but the bow stays down now and I was able to trim the engine out all the way to the third pin hole. My girl even noticed how well it was riding. Me, her, and a good amount of gear and tools and the boat touched 40mph with the 13 pitch. Slow I know, but for the first time in a while I had some hope that this little hull might be worth a dang haha. Going to drill the jackplate and get that engine up a little higher and try some bigger props.

40 mph is not slow! Good work. If my experience means anything, you'll pick up 4 to 5 mph with the cav plate at least an inch above the keel.

Jeff

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Originally Posted by Fastjeff57

40 mph is not slow! Good work. If my experience means anything, you'll pick up 4 to 5 mph with the cav plate at least an inch above the keel.

Jeff

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That's what I'm hoping for Jeff. Pretty amazing how small of a detail can make such a big difference on the water. I've only built Jeeps and street cars up to this point so it's definitely been a learning experience for me. Having some fun for sure tho.

So I haven't changed a thing since I last posted, but I'm going to take the boat out alone today and play some. Just hoping it handles about the same and doesn't bounce the bow too bad.

Might twist on the carbs a tad more. For some reason in reverse it kept wanting to die and that was a bit aggravating, but I'll get it straightened out soon.

It did pretty good yesterday. 44mph and stayed pretty flat. I didn't have anything but a fuel tank and a Gatorade so I was impressed that once she stepped up the bow stayed down. The whole boat kind of bounced maybe an inch or so at full throttle. Not sure if I didn't have the speed to hold it up on top or if I need to reduce the angle of the trim tabs a bit.

Also, randomly noticed once I loaded the boat that my trim tab anode was gone. Nothing left but a little bit around the mounting bolt. Looks like something got in between it and the prop but no real damage so I'm not real worried. Hopefully it's a cheap part.

glad to hear it's running good, but if your wanting speed that's not the hull as already stated. That hull is intended to be a heavy duty little fishing boat, great if your gonna bang off logs or rocks but a rather heavy hull for the size.

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Originally Posted by ferdthe4

glad to hear it's running good, but if your wanting speed that's not the hull as already stated. That hull is intended to be a heavy duty little fishing boat, great if your gonna bang off logs or rocks but a rather heavy hull for the size.

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I hear ya and agree. Just working with what I got until I figure out what's next. Plan was to get a 15' Weldbilt with a small deadrise, but I'm going to learn up on these Thundercats first. They look like a riot.

I'm pretty sure I can get a few more mph out of it. Wont be outrageous, but 50+mph maybe. It's fun for now though and gets me and the dogs out there.

Got a little bit of what I think is a lean sneeze going on at idle. Going to tune on the carbs one more time before I just take them off and rebuild. Also, looking at my spark plugs I think the max timing is way too advanced. Timing mark is nearly all the way at the base of the plug strap. Gonna put the gun on it and find out.

I know what you meant I fish rivers for smallmouth in my boat so I sacrifice speed for a heavy duty hull that can handle running over logs and crap. If you want to stick with a tinny, but want hull that is meant more speed look into edge boats. Lot Arkansas and Louisiana guys running them with 40-60 tillers getting good speed out of them for a boat that could still be used for taking a cruise with the gal, dogs, and a cooler.

Yea the Edge and the Havoc boats are real nice. Ride kind of like a bass boat and I hear they can soak up some chop. They ain't cheap, but I can see the value in them for sure.

I can point you to the correct people for help with your rig. Are you wanting to stay stock? No real reason for doing so.

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Originally Posted by sabine river killer

I can point you to the correct people for help with your rig. Are you wanting to stay stock? No real reason for doing so.

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That would be awesome. Just being able to ask a question here and there would be helpful. I'm not trying to stay stock at all. I want to go all the way with this Merc. Just taking baby steps as I learn. I don't really have any friends around here that know about these engines or care for hot rodding a boat so I've been learning what I can. In the garage and what I read on the forums.