performance test-does this sound right

[jdsgrog]

Hey, all.

Earlier this fall I converted my '67 Johnson 33hp to a tiller. I put the motor on my fishing rig-a modified '76 lund s-14 (14' deep v tinny) rated for a 35hp motor. Anyway, I finally was able to get it out today to give it a performance test. After adjusting the high and low speed jets, I got a top speed of 26.6 mph (gps) in weather about upper 40's. the boat was loaded with me, some fishing gear, a 6 gallon fuel tank with about 5 gallons of fuel, a deep cycle battery, bow mounted trolling motor-about 850 total pounds of displacement.

What do you think. Does that sound about right or should I be getting more speed?

BTW, the 33hp really pops the boat out on plane in what seems like an instant.

 

[Bob_VT]

Re: performance test-does this sound right

Yes that sounds like you are right on the money. The older 33 hp had the HP measured at the powerhead and not the prop..... you are actually pushing the boat with about 28-29 hp at the prop.

A true 35 hp would put you into the low 30 mph range but..... what does it matter? If it gets you to the fishing spot and home again ...... that is the true question.

 

[jdsgrog]

Re: performance test-does this sound right

Thanks for the quick reply. I had a '59 18hp motor on the boat before and was getting a top end about 17-18 with my current set up. Definitely this setup gets me to my fishing holes faster. Actually, going 25-26 mph on a tiller and an aluminum boat is quite a ride (different from my 14' fiberglass runabout that this 33hp was on before). I was pretty comfortable cruising at 18-20mph, which the 33hp makes effortless compared to the old 18hp.

 

[Bob_VT]

Re: performance test-does this sound right

Want to increase your comfort more ??? Convert the hull to a side console/center console..... with controls.

 

[jdsgrog]

Re: performance test-does this sound right

Actually, I like the tiller layout. Since this is my fishing rig, I want to keep things as open as possible. The mods that I did so far for my boat was I added a casting deck up front with a storage hatch, put in a small mounting deck for the trolling motor and a fishfinder, adding rod holders, adding cleats, and putting a couple of hatches in the middle bench for my batteries. This winter, I'm going to add a floor. I was fine with the 18hp when I was out by myself, but add another 250 lbs when bringing a buddy and his gear, the boat would bog down a few mph.

But I have to say, the 33hp shoots the boat out of the hole in literally a second or two (at least that's what it feels like). The 18hp took a while to get on plane even with only me in the boat.

 

[Chinewalker]

Re: performance test-does this sound right

It's possible you've got too little prop on your motor now. You mention the motor came from a (likely heavier) fiberglass boat and it now really pops your lummie on plane. Might be worthwhile to find out what prop pitch you're running now and seek out one that's an inch or two higher in pitch. If you know of someone with an inductive tachometer you might be able to tach it out - you want to be somewhere in the high 4000s/low 5000s with that motor. Elsewise, it sounds like a nice rig! Enjoy!

 

[jdsgrog]

Re: performance test-does this sound right

I was thinking about getting a tach for the motor, but the problem is that there is no tach that would work for that motor except the tiny tach. I'll look into it the next season. The fiberglass boat I had on it weighed in a little more than the aluminum as it was an old glasspar lido. The motor actually got that boat on plane in a few seconds. The two boats are almost identical in weight, about 50-100 lbs different (that is after the modifications I already made). I have to double check the pitch on the prop, but I thought it was a twelve inch pitch.

As for the "popping up on plane"...that was compared to the 18hp. The 18hp went on plane in more of a "smooth curve"...understandable considering I am 220 lbs and I have the gas tank in the rear.

 

[lakelover]

Re: performance test-does this sound right

Not sure of the weight of your Lund hull, but that seems like it could be a little faster with the 33. My 14' Starcraft utility at 225 lbs., with similar payload, (minus the trolling motor and you've got 40 lbs on me), and a 20hp Mercury will do 29 with just me aboard. Maybe the prop change suggestion above is a good one.

Edit: Just reread & saw above that you have a casting deck, maybe that extra weight would account for the few mph.

I had a '65 33hp Evinrude for many years & loved it.

 

[Texasmark]

Re: performance test-does this sound right

jdsgrog,

Numbers sound good to me. Like Bob says, you don't have 33 prop hp.

I have had, as have friends, rigs in your category and your numbers are good.

Having had them, I experimented with props and considering the equipment, it was a waste of money and time for the most part. For what you put into it, you got little in return.

Mark

 

[jdsgrog]

Re: performance test-does this sound right

Not sure of the weight of your Lund hull, but that seems like it could be a little faster with the 33. My 14' Starcraft utility at 225 lbs., with similar payload, (minus the trolling motor and you've got 40 lbs on me), and a 20hp Mercury will do 29 with just me aboard. Maybe the prop change suggestion above is a good one.

Edit: Just reread & saw above that you have a casting deck, maybe that extra weight would account for the few mph.

I had a '65 33hp Evinrude for many years & loved it.

Yeah, my hull weight without the mods (just straight boat) is 285lbs based on research. With the mods I mentioned, it weighs in nearly 400lbs. My motor was also trimmed slightly down because with me alone in the boat, I porpoised a bit with my old motor. But it may be different with the 33hp.

I do love the 33hp. It's actually a pretty quiet motor and the way I have it running right now, it's running smooth. Next season, I will readjust the high speed needle valve as I believe I might have some room to adjust. Last time I did that with my fiberglassic, I gained two mph. But as I said before, as I was getting up in the upper twenties with the boat as a tiller and by myself in the boat, it was plenty fast enough. I was fine going 20-22 mph. Just a different feel compared to the runabout...with the runabout with remote steer, going 27 mph seemed like nothing.