Got me a Starchief

[starcraftkid]

Re: Got me a Starchief

If you stay with the same diameter, one pitch is fine but since your pushing a much larger hull, I'd got with the largest diameter prop and jump pitch accordingly.
If the diameter is the same, I'd say your going to be around 5200-5250 or so at WOT. I would say you'll see about 175-200 RPM per inch of pitch changed.
If you just wanted to gain RPM and weren't worried about speed, I'd say jump down an inch in prop size but you would most likely loose top speed that way.
Did your dealer guy have a 12" x11P for that motor? (I see they list one at MI Wheel for that motor).

Let us know what you get with the 12p prop.

 

[MichaelP]

Re: Got me a Starchief

That hull looks to be in nice shape from here. Keep the drive alive.

 

[rheagler]

Re: Got me a Starchief

More paint stripping. I have one side done above the spray rails. So far I've put in a total of about 4 hrs and probably 1-1/2 qts of zipstrip. The weekend weather forecast looks pretty grim. I hope they are wrong.

 

[ezmobee]

Re: Got me a Starchief

Lookin' good!

 

[rheagler]

Re: Got me a Starchief

Thanks! I'm trying to get something done on it every day, so I don't lose momentum. Like I did with my kitchen & bathroom. There's plenty of time in the winter to remodel rooms though.

 

[Brenn]

Re: Got me a Starchief

Yeah thats looking great.What are you using to strip the paint off? I think you may have mentioned it earlier and if so sorry for the repeat answer.

 

[rheagler]

Re: Got me a Starchief

Thanks Brenn. I'm using Zip Strip. Black & yellow can.

 

[Brenn]

Re: Got me a Starchief

thanks good to know

 

[rheagler]

Re: Got me a Starchief

The weather forecast was wrong, that's the good news. I got the new prop on, launched after clearing a bunch of tree parts from the boat ramp. Motor started fine, pulled away fine. Throttled up to 5000 and it fell on it's face. Let it warm up some more and same thing. Went back home, fuel lines clean, Carb bowls clean, plugs a little fouled. Replaced plugs. Tried again today, ran better but still won't go over 5000. I also noticed the voltmeter pegged well past 16. I suspect something electrical, but I have read in this forum where high voltage is normal for these motors. In any event, I did get a burst of energy going and stripped paint off the entire starboard side of the boat. No pics though, it was dark when I finished.

 

[starcraftkid]

Re: Got me a Starchief

The weather forecast was wrong, that's the good news. I got the new prop on, launched after clearing a bunch of tree parts from the boat ramp. Motor started fine, pulled away fine. Throttled up to 5000 and it fell on it's face. Let it warm up some more and same thing. Went back home, fuel lines clean, Carb bowls clean, plugs a little fouled. Replaced plugs. Tried again today, ran better but still won't go over 5000. I also noticed the voltmeter pegged well past 16. I suspect something electrical, but I have read in this forum where high voltage is normal for these motors. In any event, I did get a burst of energy going and stripped paint off the entire starboard side of the boat. No pics though, it was dark when I finished.

Most of those old Mercury 50hp/500 motors were unregulated charging systems. Just a stator and a rectifier. Your charging so the rectifier is fine, either turn on some lights to use some volts or buy a universal voltage regulator.

It sounds like you need to sort out the running issue before verifying the prop.
Also, keep in mind that a bad short or draw on the charging system can put a load on the motor too, but if 16v is all your seeing, that don't sound like the case. I had a slightly older Merc 500 that would hit 20v at full throttle with nothing turned on in the boat. I wired in a common three wire solid state voltage regulator that I got from the local auto parts store.

Could there have been a running issue before keeping it from turning over 5,000 RPM or is this a new problem?

 

[rheagler]

Re: Got me a Starchief

Hard to say if it is a new problem or not. It may not even be a problem. I have much better diagnostic skills with old large 4 stroke motors. My prop dealer suggests I go lower pitch with the prop, the theory being that since my old prop was pretty beat up the new one is putting more of a load on the motor just because it is more efficient. He ordered one for me, it will be in tomorrow or wednesday. I just have to make sure I make enough time this week to get this sorted out, I'm already registered for a catfish tournament saturday.

 

[starcraftkid]

Re: Got me a Starchief

Due to the size of the boat and size of that motor I'm leaning toward you needing the lowest pitch prop available for that. You want to stay with as large a diameter prop as you can but diameter tends to affect RPM more than pitch in this situation. What size was your original prop? What size did you just try?
I see that Michigan Wheel makes a prop for the early 50hp Merc 12.5" x8P if that's what it takes, so you should be able to get the right combo.
With a smaller motor on a boat that size I'd really want to maintain as much diameter as possible for handling purposes. Too small a prop and it'll become hard to maneuver the boat, especially in strong current.

 

[rheagler]

Re: Got me a Starchief

I took most of yesterday off to get ready for the catfish tournament and got a few small things done. Added a couple rod holders, got stuff together for a portable livewell, reconfigured port side seat, altered the bimini from my old boat to work on the Starchief. But the most important thing was that the 11-1/4x10 prop came in. I got the call for the prop about the same time I got the call that the tournament was canceled due to river condition. The prop made all the difference I expected it to. My rpms jump right up to 5500, I can cruise along comfortable, although kinda slow, at 4800. It tops out at 24mph upstream at 5500, 21mph upstream at 4800. Downstream 26 at 5500, 24 at 4800. This was with the tide going out with a pretty swift current. The river is somewhat swollen from all the recent rain. All in all I'm happy, but I fully admit more power would be nice. I'll be looking for something in the 100 HP range over the winter. Anyway, here are a couple of pics from today....

 

[ezmobee]

Re: Got me a Starchief

Sounds pretty good. Not blistering speed of course but it'll certainly get you there. Nice!

 

[MichaelP]

Re: Got me a Starchief

I'd be happy with those speeds. Its not a race boat anyway. Can't wait to take pics of mine on the water.

 

[rheagler]

Re: Got me a Starchief

I'm happy with the cruising speeds, and it's fuel usage so far. What I forgot to mention though is that with such a low pitch prop, the low speed handling is pretty squirrelly. As in it's pretty hard to go slow and manuever in a strong current, which is typical for the river here. The guy who sold me the prop told me that it was likely to do that, and he was right. I've learned a lot about props this past week. Maybe I don't need to go all the way to 100 HP, but probably at least 75. Anyway, I'm in no hurry to do so with the season winding down and funds getting pretty (really) low in the boating budget. I do have a new hat that is sure to add some horsepower though!

 

[starcraftkid]

Re: Got me a Starchief

Don't bother with a 70hp Merc, I swapped out a 1973 Mercury 500 on my 16' Sportcraft years ago for a one year old Mercury 70hp back in 1984, the boat went slower and felt like I lost power. I ended up going to a 4 cylinder 85hp a year later. All I did is increase fuel usage. The best move I made with that boat was when I hung a later model 115 Mariner. I went faster, didn't have to flog the motor to get up to speed and burned less fuel because of it. I with I had kept that motor for my Starchief but let it go with the Sportcraft. I think the 115 was a 1990 or so. That too was an inline 4.


What's happening with the low pitch prop is that your not moving enough water at low RPM under that boat, thus you have problems with handling, a higher pitch prop moves more water, or takes a bigger bite with every revolution which makes the boat easier to turn.

 

[rheagler]

Re: Got me a Starchief

Took out the Starchief for the last time of the season yesterday. Over winter I will fix up the cabin, paint and change the seats. I'm not 100% happy with my low budget quasi pedestals. I will most likely go with original style folding seats. I like the idea of maximum fishing room. Anyway, first order of business will be coming up with a cover arrangement that will let me work on it without spending half the work time covering and uncovering. I should have bought a house with a bigger garage.
Last pic on the water from '11. Not that good a pic, but it's a pic!

 

[starcraftkid]

Re: Got me a Starchief

I looked at a boat a while back that had a pretty cool idea for a cover. The guy took a piece of wood and extended the winch stand to about 8' tall, then ran a single 2x6 back to a pressure treated 4x4 with a cross section for a base. The tarp was draped over the top in a real steep pitch. The ends were somewhat open to let it breath. I think he had it tied solid to one side of the trailer and attached with bungee cords at least part way on the other side. It was simple, took no tools to remove, and since it was so steep of an angle it it can't collect water or snow.
The only cost was the wood and a tarp. He had a 20' 2x6 or maybe a 2x8 running lengthwise, it was bolted to the rear 4x4 stand, and the front was made to fit in the winch stand. I'm sure the front could also be made to stand alone as well.
All he had to do to remove the tarp was to lift the front end out of the bow stand and swing it sideways and drive away.
It was tall enough to get inside and work on the boat if needed too.

 

[rheagler]

Re: Got me a Starchief

Thanks for the suggestion. I'll probably do something along those lines, but those 'garage in a box' things at Tractor Supply sure are tempting.