Johnson 75 Hp 1964 copresion

[aurora]

can somone tell me what is a good compresion reading for this motor 1964 v4a 75 Hp <br />and where i can get a new distributer cap less than 250 australian dollors sounds a bit dear to me thanks guys

 

[OBJ]

Re: Johnson 75 Hp 1964 copresion

Hi aurora...how's things down under?<br /><br />Compression in the 90's is always good but given the age of your engine and not knowing what it has been given, I would look for even compression across all the cylinders with no more than a 10 to 15% difference between them. I would make sure the compression is good before buying parts. No doubt the distributor caps are pricey even in American dollars. Check ebay or the link below might help.<br /><br /> http://www.twincityoutboard.com/

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

i have checked the comp and i got a reading of 100 lbs on all four cyl is this good do you know

 

[Joe Reeves]

Re: Johnson 75 Hp 1964 copresion

Aurora.... Compression of 100 psi on all four cylinders is ideal.<br /><br />The 1964 75hp could have either a magneto or automotive type ingition system. I may have a few distributor caps left in stock but would need to know which type you need.<br /><br />Automotive type = plug wire lead from the top side area of the distributor.<br /><br />Magneto = plug wires lead directly from the bottom (pointed straight down).

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

thanks Joe i have got a new dizzy cap now i find that i have no spark on cyl 2 and 4 new leads and new cap and roter butten now in the dizzy 2 and 4 are diagnal from each other is there any reason why ther would be no spark on only the two of them i cant work it out i have checked the points gap and it is fine do you have any clues thanks ian Australia

 

[Joe Reeves]

Re: Johnson 75 Hp 1964 copresion

Which ignition system do you have?

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

joe i have Automotive type plug wire lead from the top side area of the distributor

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

Bloody hell whats gunna go wrong next the starter motor is gone now have had it apart and the windings are shot god knows what that will cost this boat is like a hole in the water that i keep throwing good money after bad ha ha ha

 

[Joe Reeves]

Re: Johnson 75 Hp 1964 copresion

One set of points fires #1 & #3 cyl. The other set fires #2 & #4 cyl. Since #1 & #3 fire properly, obviously the rotor is okay.<br /><br />The most likely cause is either dirty points pertaining to #2 & #4 (clean with laquer thinner or acetone), or you have the condenser lead over top of the points where the rotor can fire to it rather than the distributor cap terminal (it happens but should only affect one cyl).<br /><br />The condenser lead should be slid down, away from the top area of the points as far as possible. My bet is on the dirty point scenario. I assume you are setting them on the high lobe at .020 .

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

Thanks Joe your the man will check all of them and get back to you have to fix the starter motor first have no go with out it have cleaned points i bet its the condenser lead i replaced it not long ago<br />will get new points and then try <br /><br /> thanks ian australia

 

[Joe Reeves]

Re: Johnson 75 Hp 1964 copresion

I neglected to mention..... there is a lead that connects one set of points to the other, such as the condenser connectes to one set of points, then a lead connects to that same condenser terminal and is connected to the same location on the other set of points.<br /><br />If that lead is not there, or is there but faulty, there will be no ignition to two cylinders.

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

Joe i have got the starter motor in getting rebuilt shoud be back in a couple of days <br />can you tell me what sort of coil i should can i just use one from the auto shop that go,s on a car any clues thanks ian

 

[aurora]

Re: Johnson 75 Hp 1964 copresion

,