1975 Mercury 1150EL Ser#4115082......help

Hi i have the engine listed above, getting no spark at any of the cylinders. I have performed a number of tests suggested and am still stumped. I'm looking at either the Trigger or Switchbox as possible faults, both of which are expensive...anyone have any leads as to where i can obtain either parts much cheaper? or any advice to an easier or less costly solution?<br /><br />Thanks a bunch

Re: 1975 Mercury 1150EL Ser#4115082......help

First things first. Does your motor have a distributor? And what are the tests you have already performed?

Re: 1975 Mercury 1150EL Ser#4115082......help

You will need to disconnect the mercury switch first, then see if the red post on the switch box has 12v. to it at all times, if so then ck the white should have with the ign. on, if it does, disconnect the blk lead on the dist. side of the box and install a jumper wire between the brn and white posts, then with the key on arc the blk post to grd. you should get spark with each arc. if you don't the box is bad if you do the trigger is bad

Re: 1975 Mercury 1150EL Ser#4115082......help

this is the test i performed and the results i got...and yes it has a distributor<br /><br />1. +12 v at red terminal<br />2. +4-5 v at white terminal<br />3. no spark touching black ground<br /><br />MERCURY BATTERY-POWERED CDI TEST<br />FOR DISTRIBUTOR MODELS<br /><br />This test is for the 332-2986 switchbox used from 1967-1978 on all the inlines.<br /><br />This test assumes your coil is good (most all are).<br /><br />DISCONNCT BATTERY<br /><br />1. Turn off ignion<br />2. Disconnect all 3 wires on the distributor side of the switchbox.<br />3. Remove the HV lead from the coil to the center cap (remember it unscrews<br />from cap)<br />4. Reconnect that HV center lead to the COIL side only.<br />5. Position that HV lead about about 3/8" from ground (block, shrouds etc)<br />and find a way to hold it there.<br />6. Jumber the brown and white terminals on the dist. side of the switchbox<br />together.<br /><br />RECONNECT BATTERRY<br /><br />7. Check that you have +12 V at red terminal.<br />8. Turn on ignition and verify +12V at white terminal (on red terminal side)<br />9. Touch the black terminal to ground - unit should cause spark each time<br />you touch ground.<br /><br />If that passes and it won't fire at all, suspect the trigger

Re: 1975 Mercury 1150EL Ser#4115082......help

i also did what you said with the jumper wire...got no spark. does this mean im assuming the switch box is bad?<br /><br />thanks

Re: 1975 Mercury 1150EL Ser#4115082......help

Your voltage on the white terminal is very low. It has to be the same as you get on the red lead.<br /><br />Laddies can advice if you can put a temporary jumper in there.

Re: 1975 Mercury 1150EL Ser#4115082......help

i used the jumper and got 12v on the white terminal as well...still no spark

Re: 1975 Mercury 1150EL Ser#4115082......help

Very, very, strange that you needed a jumper to get +12 on white. Sounds like you might need to troubleshoot ignition switch and wire harness FIRST - then troubleshoot the primary ignition.<br /><br />If you get real stuck, and need immediate help, follow my webpage link to my phone number and shoot me a call.<br /><br />-Wayne<br />PS: Please fix your avatar image - it's huge!

Re: 1975 Mercury 1150EL Ser#4115082......help

Looks like a bad trigger. Do as Clams said find out why only 4.5v on white wire. You can get a used trigger for around $200.00. Talk with Clams and he can help you ;Most all he fools with is inlines. He is the inline Man.<br />Good Luck, Tim

Re: 1975 Mercury 1150EL Ser#4115082......help

Didnt realize that picture would be so big, sorry bout that. Ill get on that troubleshooting as soon as i find it in my manual, hopefully its in there. Thanks, ill repost afterwards.

Re: 1975 Mercury 1150EL Ser#4115082......help

Ok, ignition switch - check...having some trouble finding a troubleshoot procedure for the wiring harness, what I can tell is that the wires going to and coming out of the harness look twice as old as me and have more cracks than a 20 year olf parking lot....

Re: 1975 Mercury 1150EL Ser#4115082......help

if theres any way to post pictures on this to show you, lemme know how to do that

Re: 1975 Mercury 1150EL Ser#4115082......help

Ok im posting a rediculous amount, I know...but I'm looking at the wiring diagram for my engine, and the coil on my engine is not the same as in diagram, but it is the same coil as a diagram for a 1976-78 of the same model...and then theres my ignition, its scary looking, terrible wiring, id love to be able to post pictures of this.

Re: 1975 Mercury 1150EL Ser#4115082......help

Re: 1975 Mercury 1150EL Ser#4115082......help

You don't need to post a picture. I've replaced 100 of the internal harnesses in the motor. They just turn to dust - I know.<br /><br />They used 2 different coils - the same electricly.<br /><br />Search for "Mercury internal wire harness" on Ebay and you'll be ahead of the game, trust me.<br /><br />-W

Re: 1975 Mercury 1150EL Ser#4115082......help

oldmercs.com has them

Re: 1975 Mercury 1150EL Ser#4115082......help

You can replace one wire at a time. The best and easy way is to go with a new harness. It don't take long To tie up a few $$$ when fixing up a old motor; But look at what new cost. Eather way you have to pay to play... Tim

Re: 1975 Mercury 1150EL Ser#4115082......help

10-4 on that Tim, Thanks again guys.