Mercury 115hp...no sparrrkkk

[skloczko]

I just received a boat from a friend with either a late 70s or early 80s mercury 1150 engine (115hp) found a few wiring problems with it by looking through wiring diagrams, engine will crank well, but no spark at any of the six plugs. Any idea what i should look at first? Also, I have heard something about a mercury switch and a tilt switch, what do i do to test these? The serial number on the engine is 4115082

 

[dakk1]

Re: Mercury 115hp...no sparrrkkk

Hey Klutchy<br /><br />Look at this link for some ideas:<br /><br /> http://outboardparts.com/troubleshooting/troubleshooting7.htm <br /><br />Also, that mercury switch can be tested with an ohmmeter. Disconnect from motor and connect meter between ground lead and the orange switch lead (some are black/yellow). Hold the switch as it would be with engine in down position. Should show no continuity. Hold switch in up position. Should show continuity. Probably going to need a manual at some point. Good Luck.<br /><br />Dave ...

 

[timmathis]

Re: Mercury 115hp...no sparrrkkk

On A mercury switch all you have to do to test is disconect it and it will run if it is bad!

 

[Clams Canino]

Re: Mercury 115hp...no sparrrkkk

If this is a distributor motor it's pretty easy to test the switchbox too. What Tim said about the Mercury switch.<br /><br />-W

 

[skloczko]

Re: Mercury 115hp...no sparrrkkk

Ok, i just tried this check and it failed, I got:<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 />My question is...what do i replace or fix??<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

 

[emckelvy]

Re: Mercury 115hp...no sparrrkkk

If you have just 4-5 volts on the white terminal, that could be your problem. The white terminal receives switched +12V from the ign, when the key is turned to either "START" or "ON". <br /><br />Only when there is +12V on both the red and white terminals will there be spark.<br /><br />Try attaching a jumper wire from the red terminal on the switchbox to the white terminal, or just a "hot" wire from the positive terminal of the battery. Then see if there's spark.<br /><br />You definitely won't to get spark with 4-5 volts on the white terminal.<br /><br />Cause of the problem could be as simple as a bad ign switch, or trouble with the wiring (I've seen the red or white wires in the external harness break from flexing when the motor turns, or from corrosion), or just a corroded pin in at the external harness's connector plug.<br /><br />Just to be sure, we're talking about the white terminal on the side of the box opposite to where the (3) distributor wires connect; same side as the constant +12V connection (red terminal).<br /><br />HTH...........ed

 

[Clams Canino]

Re: Mercury 115hp...no sparrrkkk

Red outta be +12 all the time and white +12 when key is on.<br /><br />-W

 

[skloczko]

Re: Mercury 115hp...no sparrrkkk

ok, i tried that jumper wire, now the test checks out good, but still no spark at the plugs...

 

[fish4fun2]

Re: Mercury 115hp...no sparrrkkk

Klutchy I have the same problem with my merc in line 6 from the same era as yours (no spark at all) I have 12v on the red and 12v on the white when key is in the on position. Here is what Bob posted for me to try but I did not understand it totally...<br />Turn your engine to number 1 and install a spark gap in the plug wire, install a jumper wire between the brn and white wires on the dist side of the switch box, disconnect the blk wire same side, turn the key on and arc the black post to ground. You should have spark on each arc, no spark bad switch box, spark bad trigger.<br /><br />If you understand all this stuff write back and tell me in simpler terms thanks

 

[timmathis]

Re: Mercury 115hp...no sparrrkkk

Go to Outboardparts.com Then click on mercury. Then click troubleshooting. Then click on print guide. This will tell you step by step on how to test with pic's. Easy as 123. Then take 2 asprin. Test and find your problem, And post us in the morning. Tim