75 searay srv 240

[Staaannnn66]

Hi. First time here. Bunch of knowledgeable people​.

As you can see. I have a 75 searay srv 240.. just got it. I'm pretty fimilar with engines and stuff. But I'm not getting spark. When I take off the two wires on the + post of the ignition coil, and test them. (While off coil) I get a full 12v!!! Once them wires are on coil. It drops down to 5.5v... something isn't right. Im stumped

 

[Scott Danforth]

welcome aboard

new to you motor with points. suggest you file the points, re-gap them and then go from there. or better yet, change the points and condenser, re-gap them and go from there.

you have either a ballast resistor or a resistor wire feeding the points. your points only get 12 volts during cranking.

this is points ignition 101 http://classicmechanic.blogspot.com/2011/03/ignition.html

 

[Staaannnn66]

I have just recently purchased a 75 srv 240 and I'm not getting spark.. I have replaced points and gapped at .020. new condenser. New ignition coil. Still no spark. I'm getting 5.5v at + post of ignition coil when the key is on. Bit when you crank the motor over it jumps to 8.5-9v

Still no spark. New plugs as well.

The boat was sitting for a couple few 8 years.. do you think it could be dirty connections throughout​?

Thanks!!

 

[Staaannnn66]

I cleaned starter connections and noticed the Spade in the distributor was touching the bottom of the distributor.. put that on the top.

Now I have 12.5v at the + post of coil WITH the points OPEN...

Still no spark at grounded plug(I know I should get a tester, short on cash currently )

My next guess would be a cap and rotor? Agree disagree? Why?

 

[Staaannnn66]

I appreciate the input guys!! I'm decently stumped!!

 

[Scott Danforth]

go back to points basic. your gap is .020 with points open, do they actually close? all you need to verify is a test light or a free multi-meter from harbor freight. also, even with new points, you need to file them

you should be able to set the points in the field with a match book as a guide. points are the simplest ignition system on the face of the earth for multi-cylinder engines.

one end of the point wire goes to ground, the switched end goes to negative side of coil. +12 volts to the plus side of the coil (ignoring ballast resistors and the I terminal on the starter). assuming that the points are opening and closing, you will have the coil building a charge for every lobe on the dizzy camshaft.

the rotor simply points that charge to one of the spark plug towers on the cap, which is wired to a spark plug.

 

[Staaannnn66]

Yes, with the points being open. I have 12v at the + post.

I don't think there's a ballast on this vessel..

I have a multi meter I used.

But when the points are closed.. what should the voltage be at the + post of coil??

 

[Scott Danforth]

Yes, with the points being open. I have 12v at the + post.

I don't think there's a ballast on this vessel..

I have a multi meter I used.

But when the points are closed.. what should the voltage be at the + post of coil??

with points you need to run a resistor wire or a ballast resistor, or you burn the points up in about 3-4 hours

the points are the switch to ground for the coil. on the primary side coil terminals, you should see ground on the - side of the coil and wither 9 volts (ballast resistor) or 12 volts while cranking (from the i terminal on the starter) on the + terminal. on the secondary side of the coil, you should see an instantaneous voltage of 35,000 - 50,000 volts when the points open as the coil discharges.

 

[Bondo]

Ayuh,.... Just what is this motor yer workin' on,..??

Merc,..?? OMC,..?? Volvo,..??

 

[Staaannnn66]

Hey thanks for the reply bondo! Its a 76 351 merc i believe.. Got the sumbitch running tho!!


Now I'm hunting down the correct stearing cable replacement and can't seem to find one.. Do you know a reliable site?

Thanks!