What propeller on johnson 60

[jokeri]

I have my Johnson SeaHorse 60 '82 taken out of the boat, and I'm gathering whether or not to chance a new propeller .. I already have a propeller size 13 1/4 x 17 but I'm not sure if it is suitable for the motor. The boat is 5,6 x 2 m HT.

 

[catfish1]

Re: What propeller on johnson 60

is that 17ft long? if so, a 17 pitch prop would be close! but you need to get a tachometer reading at WOT in order to know if the prop is the right pitch. what you want is 5500 rpm at WOT (wide open throttle).<br />is the boat aluminum or fiberglass? and also, i thought that johnsons of that year and HP were small gearcase, and would make that 13 1/4" the wrong diameter. i think what you want is a 11 3/4 x 17p

 

[jokeri]

Re: What propeller on johnson 60

Well, I calculated it's 18 legs long (why don't you switch to SI - system like everyone else has done?)---joke joke joke... What kind of tachometer can I attach to it? With my recent propeller there is no problem achieving the maximun rotation speed. If I do a WOT on a low speed, the engine is cavitating. That's why I think my propeller is too small.<br />The boat is made of wood, covered with fiberglass. (= relly hot rod !!)

 

[catfish1]

Re: What propeller on johnson 60

so your running this prop right now? are you sure this is a 1982 mod 60hp johnson? because i checked, and this model motor is in fact a small gear case. a 17p prop for your motor should be 11 3/4x17 "not" 13 1/4x17 either your motor is not a 1982, or you have the wrong prop on it now.<br />ventilation: where is your cavitation plate, in relation to the bottom of the transom? it sounds like you may be a tad high, or the motor is trimmed out to far at "take off"

 

[rickdb1boat]

Re: What propeller on johnson 60

I'm showing a 12-1/2 X 13" prop for that size boat and motor. An 18' boat is alot for a 60 HP motor to push and therefore needs a lower pitch prop. The 17" will lug the motor, deteriorate preformance and eventually damage the motor.

 

[catfish1]

Re: What propeller on johnson 60

point is, 13 1/4x whatever pitch would be for a large gearcase. we will need to know the year, size, & make of the motor to get close to the right prop! you will definitely need a tachometer if you want it proped correctly.

 

[jokeri]

Re: What propeller on johnson 60

Serial numbers are J60EL6TB and BO14876.The prop I have used until now has no size printed on it. It's a little bit tricky to measure but I would say it is 11 1/2" diameter and pitch (the "length" of the prop, dont know how it is measured) is 4 1/2". See picture in this link: http://jokeri.mine.nu/prop.html <br />The boat achieved speed of 20 knots with 2 persons onboard. I wonder if any prop would do any better?

 

[rickdb1boat]

Re: What propeller on johnson 60

I don't know what pitch it is by looking at it, but as I said, 13" should be close, depending on the weight of the boat and load carried.( The boat is made of wood, covered with fiberglass) I would get ahold of a prop shop and speak with them about it. Also, can you double check this number?<br /><br />J60EL6TB

 

[catfish1]

Re: What propeller on johnson 60

ok, i dont know what 20knots is, compared to mph but i'm guessing that would be 30mph. which would be good. the only way to know if your in the right rpm range is to put a tachometer on it, the rpm should be around 5500 at wot. if its considerably less than that, you are lugging the engine.<br />you say that if you open the throttle up fast that the prop cavitates; get a straight edge and put it on the cavitation plate, with the engine tilted down to the transom. measure the distance between the straight edge and the bottom of the transom. the cavitation plate should be level with the bottom of the transom, or about one inch (2.5cm, i think) above it. let me know what you find out.

 

[catfish1]

Re: What propeller on johnson 60

rick, do you know what 20knots would be in mph?

 

[rickdb1boat]

Re: What propeller on johnson 60

About 23 MPH<br /><br /> web page

 

[rickdb1boat]

Re: What propeller on johnson 60

Just for a little comparison, I have a old 67 16' Wellcraft runabout(Fiberglass and heavy) that used to have a 65 HP old merc on the back and I hit 36 MPH with 2 aboard. Now have 28 HP johnson on it and still get 30 MPH.<br /><br />

 

[catfish1]

Re: What propeller on johnson 60

23mph <br />i believe rick is pretty close with the prop size, i'd bet your engine is lugged pretty badly with the 17p. you may even pick up a couple mph with a 13p! but like i said, the only way to know for sure is to get a tachometer. every boat should have one!

 

[jokeri]

Re: What propeller on johnson 60

OK , the issue was originally, whether I could use this big propeller as a spare one or not. So it's obvious it is too big.<br />Yhe serial is J60ELCTB I think, there are scratches on tle plate. I couldn't measure the elevation of the cavitation plate, because the motor is taken out of the boat (it's winter here).Maybe this picture helps.

The motor is maybe too small for this boat, but it works fine.

 

[rickdb1boat]

Re: What propeller on johnson 60

Amen on the Tach, Catfish. It's the only way to know for sure. I have found in the past that a decent prop shop can call it pretty close. If it were me and I had no idea what to use or what I had, I'd be paying them a visit, with the prop in hand.

 

[catfish1]

Re: What propeller on johnson 60

sorry jokeri, i didnt realize your original question was whether you could use that prop as a spare. the answer would be yes, if that is whats on it now! i think if it were me i would get a tachometer first. then run the boat at wot. then take the prop to a prop shop and tell them what your wot rpm is. because it seems you really dont know what the prop pitch is, since there are no numbers on it.<br />by the way, nice boat!

 

[rickdb1boat]

Re: What propeller on johnson 60

jokeri <br /><br />Hard to tell where the bottom of the hull is from the pic, but it looks close to being the right height, but may be a bit high. Yes, you could use the prop you have now for a spare with no problem for emergency use. You could also have it re-pitched and possibly avoid having to buy a new one. Or do both! By the way, that's a 1983 Johnson Motor ya got there. I would look further into the mounting height. Looks like you have room to go up with it a couple holes. Take a look at it again when you get it back on there.<br /><br />

 

[catfish1]

Re: What propeller on johnson 60

that should be the setback i think. there is no way to tell from looking at that picture whether the motors up too high or not.

 

[jokeri]

Re: What propeller on johnson 60

Yes I realized the motor is too low mounted and that is one of the reasons I took it out of the boat.<br />Thanks to all.

 

[catfish1]

Re: What propeller on johnson 60