'57 18 horse johnson wont plane

[gulubdur]

Hello folks,<br /> I have never posted on here before. I have found answers to many of my quetions without haveing to, thanks guys.<br /> I have inherited a 1962 glastron skijet 140v, its 14 foot. The boat was in rough shape but it floats with no leaks. I added 3/4" plywood floor and seats. The seats pulled out of the old floor. I put a battery and trolling min kota on it. FF depth finder also. Now for the power plant I have a 1957 johnson seahorse. Its the 18 horse model. It wont plane. the boat only goes about 7-8 mph. I dont have a tach but it seems to run slower than it should. I have a 9 1/4"x11 prop. All the weight minis my own girth is in the back. Do any of you think maybe I got the wrong pitch prop? Or is it a weight distribution problem? I believe the moter isn't under powered for my boat but maybe it is. Its a vary wet ride splashing through all the waves instead of over them. any help would be appreciated.

 

[gulubdur]

Re: '57 18 horse johnson wont plane

Oh can anyone tell me were to get a tach for this motor and what does WOT mean?

 

[tashasdaddy]

Re: '57 18 horse johnson wont plane

thats a small motor for that size boat. if the seats pull out of the floor, that probably means you have rot, and probably a waterlogged problem. i have a '55 15hp rude thake pushes a 14' alum v hull quite well.

 

[rolmops]

Re: '57 18 horse johnson wont plane

Welcome aboard.<br />The old fiberglass boats are quite heavy and the 3/4 inch plywood does not help any.You could try to put your battery in the front end of the boat.<br />Another thing with these engines is that they are not standard size.The short shaft is 18 inch instead of 15 while the long shaft is 23 instead of 20.<br />If you can manage to set the angle of the engine on the transom just right and lift the engine about 3 inches on the transom(piece of wood between bracket and transom)you may see a very different performance.All of this is under the presumption that the engine performs properly.

 

[surlyjoe]

Re: '57 18 horse johnson wont plane

I dont think the 18 will plane that boat. maybe a 25 but that might not do it either..

 

[Chinewalker]

Re: '57 18 horse johnson wont plane

I'm inclined to agree that the seats pulling out is indicative of a much bigger problem - water in the hull. Waterlogged foam flotation, rotted stringers, etc. are all going to weigh it down. Plus you're carrying a battery and electric kicker motor, too. Factor in that it is a wide, fairly flat hull and you need a fair bit of kick to get it over the hump.<br /><br />It's also possible that the 18 is not up to snuff and may only be running on on of two cylinders. Lots of posts here on diagnosing ignition issues...<br /><br />Good luck!<br />- Scott

 

[tmcalavy]

Re: '57 18 horse johnson wont plane

That's a stout old Johnson, but you're probably underpowered on that big a boat. If you can, pull the Johnson and run it on a smaller boat. I have the same outboard on a 54 V-hull tinny and it really moves out. If its the original prop the pitch is probaby correct as long as you match to the right sized boat. Mine is a three blade prop, but don't know the pitch...it will push the tinny up on plane in a minute or two with two big-ole-boys and plenty of gear and tackle on board. You can run the whole rig across a road scale if you want to get a rough weight and see if waterlogging, etc., has made it heavier than normal.

 

[tashasdaddy]

Re: '57 18 horse johnson wont plane

add some accessories to my 14'/55 15hp rude this week, stick steering and remote control at middle seat. it really screams now, only the last 3' of the hull in water @ wot. bow doesn't go up, it just jumps on plane.

 

[tmcalavy]

Re: '57 18 horse johnson wont plane

Hey tashasdaddy,<br />How did you do the stick steering? Got any pix? I'd love to do that on the old tinny so I can move my behind forward a whole seat.

 

[Texasmark]

Re: '57 18 horse johnson wont plane

Glastron built Fiberglas boats. Cannot compare a 44 year glass boat to an aluminum boat of any age, 44 years or not.<br /><br />Besides water absorption, back in those days, some mfgr's used an air box between the floor and the hull.....no foam, just air. Well over the years the deck to hull interface leaks and the area fills with water; lots of water and it's heavy. BTDT<br /><br />I couldn't plane out a 13' glass boat with this problem with a 23 hp Scott Atwater.<br /><br />Sorry sir, but you aren't going to get there from here.<br /><br />Now if you had a 44 year old Alumacraft Aluminum or the likes with your 18 then you wouldn't be on here posting as you wouldn't be having this problem.............probably.<br /><br />My 2c<br /><br />Mark

 

[gulubdur]

Re: '57 18 horse johnson wont plane

I thought the 18 was under powered. A guy up the street has a 1958 or '59 35 horse evinrude lark. The guys a friend of the family and offered the motor to me for $50 and I bought it. I replaced the plugs, oiled up the cyl., gassed her up and IT RAN!!! I put a steel plate on the transom to support the motor. I put the boat in the water and cruised around at slow speed and made some carb adjustments. after letting the engin warm up good I opened it up. It was a little apprehensive in the transition from slow to fast, but it planed. after a short ride I cruised back into the channel and slowed down when I heard this awful WHACK. The engine stalled and I used the trolling motor to get back to the dock. Then I started it again. It only ran on one cyl. but there was no other metal on metal sounds. So I pulled one plug and the electrode is bent down to the center electrode. I think the piston wacked it. The plug is a J6C, same as my 18. I think it maybe the wrist pin or connecting rod bearing may have some slop. Im going to put a screw driver in the plug hole tomarrow and check the piston for wiggles. If it is one of those, then engine will need to be rebuilt. I have a manual and it doesnt look harder than a dirtbike motor but I cant find a kit for it anywhere. The local 'rude dealer told me to give it up and cut my losses. First, if I do go through it and fix it, will it cost more than the motors worth? Second, were do I get a kit for this motor? The model number is 35514. thanks again.

 

[tashasdaddy]

Re: '57 18 horse johnson wont plane

tim mc, see my new post in boats not repair. 1960 lonestar 1955 15hp evinrude.

 

[Paul Moir]

Re: '57 18 horse johnson wont plane

What kind of a kit are you after? Gasket kit?<br /><br />Determine what failed. Perhaps something got into the cylinder. Since most the bearings are roller, slop would mean catastropic failure. <br />Complete engines come up on ebay al the time pretty cheap. I think you could even use a 40hp block.

 

[snowmobilefanatic]

Re: '57 18 horse johnson wont plane

i think if your guna go for a "budget" savings buy another 35 horse that all the parts whould interchange and just use the one you have now for parts so if anything ever breaks you always have a part for it. buying a whole another outboard whould be just as much as rebuilding the engine. i did the same thing with my 15 Evinrude