Following up your advice!

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Hoosier Daddy

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OK I "Really" like the idea of not jumping on the rebuiled wagon right away. So I went out and took a look at the 1974 85hp Johnny. After lookin around I found some lose screws, tightened them (duh). But after taking the intake cover off the carbs, I found the gasket disformed,(will replace asap), but there is oily residue all over the front of motor and in the water trap in the boat. I know this can not be right,(or is it?) being green it has to be from carbs or fuel lines, right? And the fuel lines have zip ties for hose clamps (probably the source of leaks.) But can this have anything to do with the reduction in power? low end is fine, but high rpm's are just not there with any real load in the boat. Maybe a carb rebuild? I would think that a 85hp motor would be able to carry a couple of passengers and a ski'er but LOL no way :( . Is 35 a good speed for my boat? 1974 slickcraft 17ft Tri-haul w/"74" 85hp Johnson? As you can probably tell Im a newbie. But learnin quick ;)
 
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ezeke

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Re: Following up your advice!

Hi Hoosier,<br /><br />You can easily check to see if your fuel leak is from the fuel lines by putting a little steady pressure on the primer bulb and watching the lines with the engine off. <br /><br />It will help everyone if you don't jump your thread, so please don't introduce a new topic each time, just go back to the original topic and tell everyone what you are doing. <br /><br />BTW, if you pull skiers, you might want to lower the pitch on your prop a bit, it may solve your problem.<br /><br />Good luck!
 
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Hoosier Daddy

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Re: Following up your advice!

Sorry, new to this since the change of forum style
Originally posted by ezeke:<br /> Hi Hoosier,<br /><br />You can easily check to see if your fuel leak is from the fuel lines by putting a little steady pressure on the primer bulb and watching the lines with the engine off. <br /><br />It will help everyone if you don't jump your thread, so please don't introduce a new topic each time, just go back to the original topic and tell everyone what you are doing. <br /><br />BTW, if you pull skiers, you might want to lower the pitch on your prop a bit, it may solve your problem.<br /><br />Good luck!
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Hoosier Daddy

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Re: Following up your advice!

after removing the prop and looking for numbers reveiling the pitch I can find nothing. is their a way to figure the pitch? The prop came with boat and motor when I bought.
 
rickdb1boat

rickdb1boat

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Re: Following up your advice!

Best way is to take it to a prop shop and they can tell you right away..
 
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ezeke

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Re: Following up your advice!

Were there any numbers or names on the prop?
 
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Hoosier Daddy

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Re: Following up your advice!

ok after looking (with steel wool and sand paper) at the prop, I found some #'s. It's a Michigan alum prop. At the rear, where the nut is is says Michigan P J 90 Cup and on the side it says 88 39 and thats all I can find on the prop anywhere. If anyone can figure the pitch to this I would be greatful. The recommended pitch for the 17ft'er is 19 but Im not sure. Again this is a 1974 17ft Slickcraft w/ 1974 85hp Johnson. Anything???????
 
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Solittle

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Re: Following up your advice!

What rpm are you getting at WOT? That will tell us if you are pitched correctly. In the dark I would guess that a 17" prop would be in the ballpark.
 
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ezeke

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Re: Following up your advice!

According to our host, the PJ90 is a 13.25 X 17(pitch) web page <br /><br /><br />So if you wanted to get out of the hole faster, you would go to a 15 pitch or use a stainless prop.
 
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Hoosier Daddy

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Re: Following up your advice!

"Thanks so very much" I have been trying to determine that for a while. Will going stainless really help? W/same pitch. Or should I just go down to the 15? Any suggestions?
 
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ezeke

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Re: Following up your advice!

Stainless costs a lot. I've got several that I don't use because they did not get the job done. You have the price of trying the 15 pitch there on the web site so why not try it out?<br /><br />It will definitely give you more pulling power and get you up faster, plus you will have a new prop with no defects.
 
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Hoosier Daddy

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Re: Following up your advice!

Sound good, Thanks. Hey I have heard of venting the prop by drilling holes in the housing of prop so the gases vent over the blades. Is this posible and does it work if so?
 
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Hooty

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Re: Following up your advice!

I can't see where you've posted the engine speed a wot with the present prop. That's real important when trying to determine which prop iz proper.<br /><br />c/6<br />Hooty
 
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moderator1

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Re: Following up your advice!

Hoosier Daddy <br />Member # 45183 posted July 07, 2004 01:21 PM<br />--------------------------------------------------------------------------------<br /> Hi,<br />I have a 85hp 1974 Johnny sitting on an 1974 17ft. Slickcraft Tri-haul and does not seem to have the right amount of power. She starts and runs fine. But (1.) I cant get out of the hole with a full load (or takes forever), (2.) will only do 35 @ best with just me or a full load. I have not done a compresion test, but am somewhat sure it is in need of a overhaul, Is there a good inexspensive place to buy rebuiled kits? I can rebuiled just about anything, but have never tryed an outboard, any tips?<br />Thanks for anything you got!! <br /> <br />alcan <br />Member # 5496 posted July 07, 2004 01:44 PM<br />--------------------------------------------------------------------------------<br /> Hi Hoosier<br />Before jumping into a total over haul, there are several tests you need to conduct. Odds are this motor just needs some service work. There is nothing inexpencive about outboards. To end up with the best results for the least amount of cash and head aches, buy a manual,read it,follow the diagnosic procedures. When you need clairification or tips on some of the fine points,that is where we can help the most. Good luck, hope to here of your progress. <br /> <br />DJ <br />Member # 5471 posted July 07, 2004 06:52 PM<br />--------------------------------------------------------------------------------<br /> You can start here.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000016 <br /><br />A 17' Tri hull is NOT a light boat. The 85 was rated at the powerhead, not the prop. Still, it is a potent engine.<br /><br />Without knowing your top speed rpm, you are guessing. The engine should be able to turn 5500 with a light load in the boat. If not, you are overpropped. <br /> <br />moderator1 <br />Member # 17886 posted July 07, 2004 11:00 PM<br />--------------------------------------------------------------------------------<br /> You've got two posts going.
 
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ezeke

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Re: Following up your advice!

Venting the prop is minor + or - stuff for guys who have perfectly balanced and synchronized motors. <br /><br />If I'm not mistaken, the 1974 used a 3.5 cylinder so you could move it to a 115HP with the right carbs and reeds. You don't have the cooling capacity for 135HP. Most important thing now is to get the motor running well and performing right for your specific applications.
 
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Hoosier Daddy

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Re: Following up your advice!

Thanks everyone!! Just an off the wall ?? with differant carbs and reeds, I can make the same motor a 115hp? souds to good to be true lol.
 
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oldgreybeard

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Re: Following up your advice!

For what it is worth. I am bringing back to life an older (1976) Larson Tri Hull with a 135 Johnson I have owned since new. The tri hulls are heavy with quite a bit of wetted area. The best I ever got out of mine was 38 MPH with a stainless prop. (17" pitch) The dealer I bought the motor from spent considerable time with me as we both thought the boat should do better. No hook in the hull, engine reaching correct WOT speed and 38 was the the top end. The dealer even had an OMC rep out on the boat working the carb jetting trying to get more. The same boat with a 70 HP Johnson did 31 MPH top end. I thought an extra 65 HP would have done more but it seemed that that was the limit of the hull. You may not see that much difference by boosting to 115 HP. Good luck, been there done that.
 
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mrc

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Re: Following up your advice!

Usually you would have to adjust the intake and exhaust ports as well to see a HP boost from new carbs.
 
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Hoosier Daddy

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Re: Following up your advice!

Just heard about planing foils and trim tabs.<br />Will a foil help the hole-shot and planing? Or should I save my money and buy a new fishing pole?LOL Any advice?
 
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Hooty

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Re: Following up your advice!

Once more.<br />What is the maximum engine speed, in revolutions per minute, with your present prop?<br /><br />c/6<br />Hooty
 
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