Mercury 150 xr4 no spark. Any thoughts?

[travisb5470]

I have a mercury 150 xr4 with no spark at all. I'm thinking it's the stator or trigger. I will replace them both after I check the kill switch. Everything I have read as to troubleshooting mentions a DVA meter. What is a DVA meter? A standard volt meter won't work? Most importantly if I index the flywheel to tdc of the #1 cylinder would I still have to check the timing? Any leads on where to get new parts?

 

[Chris1956]

Re: Mercury 150 xr4 no spark. Any thoughts?

First disconnect the ign killer wires (Black/yellow) at the switchboxes, and see if spark returns.

 

[wired247]

Re: Mercury 150 xr4 no spark. Any thoughts?

A dva meter or a dva meter attachment for a standard multimeter takes the high reading and displays that when that pulse is too faster to register normally. Its kind of like a budget oscilloscope where you can take peaks but not read the waveform. In any case to your second question unless you changed the timing it is unlikely or impossible for the timing to change on its own. Idle timing to book specs only gets you into ballpark anyway. Outboards for the most part adjust the idle speed with the timing because its easier to do it that way than to sync the carburetors throttle plates at idle the way you would on a multi carb car engine with an air flow syncronizer. The specs given for idle timing have to be adjusted for throttle shaft leaks , reed condition , ring seal etc. None of that matters in your case as you cant check it anyway. You have no spark. Check the black/yellow wires. Parts are available all over the place depending if you want factory new/used or aftermarket. Ebay can be your friend.

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

A dva meter or a dva meter attachment for a standard multimeter takes the high reading and displays that when that pulse is too faster to register normally. Its kind of like a budget oscilloscope where you can take peaks but not read the waveform. In any case to your second question unless you changed the timing it is unlikely or impossible for the timing to change on its own. Idle timing to book specs only gets you into ballpark anyway. Outboards for the most part adjust the idle speed with the timing because its easier to do it that way than to sync the carburetors throttle plates at idle the way you would on a multi carb car engine with an air flow syncronizer. The specs given for idle timing have to be adjusted for throttle shaft leaks , reed condition , ring seal etc. None of that matters in your case as you cant check it anyway. You have no spark. Check the black/yellow wires. Parts are available all over the place depending if you want factory new/used or aftermarket. Ebay can be your friend.

So basically if I index the flywheel and nothing gets moved the timing wouldn't be an issue? Are there black/yellow kill wires on each switch box?
I'm going to replace both stator and trigger if it's not the kill switch.

 

[Chris1956]

Re: Mercury 150 xr4 no spark. Any thoughts?

Yes, there should be a black/yellow killer wire on each switchbox. Make sure the switchboxes are still grounded to the block, after you remove them to get to the inner box kill wire.

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

Yes, there should be a black/yellow killer wire on each switchbox. Make sure the switchboxes are still grounded to the block, after you remove them to get to the inner box kill wire.

So to just to be sure I can switch out the stator and trigger with out throwing off the timing. If I index the flywheel and replace exactly as removed?

 

[wired247]

Re: Mercury 150 xr4 no spark. Any thoughts?

Do you not own a timing light? Get one. Theyre like $40. Timing one is not a big deal.

The flywheel comes off and goes back on one way. If you replace the stator and/or the trigger the timing might be the same if you get lucky. It probably wont be because the stator and trigger control the timing and manufacturing variances are all over the place from one lot to the next.

 

[quicktach]

Re: Mercury 150 xr4 no spark. Any thoughts?

IMHO, it's a good idea to get the CDI Troubleshooting manual and get a DVA attachment (and a good meter) and do more electrical tests before starting to replace parts. Once the parts are bought, they're not returnable. A good rule is that if everything around a switch box tests OK, by default, it's usually the switch box that's on the hummer. Even a simple VOM test on the trigger and stator can give an idea if resistances are within an acceptable range....Also, get a manual for the motor.

 

[CharlieB]

Re: Mercury 150 xr4 no spark. Any thoughts?

You seem to be in a big hurry to spend a LOT of money on ignition parts that you may NOT need.

The whole purpose of troubleshooting is testing to determine exactly what went wrong so that you only spend what you NEED.

The very first thing you need to test is for spark. A good battery, fully charged, with CLEAN connections on EVERY cable end is necessary to provide the starter the current needed to turn the motor over above the MINIMUM CRANKING speed of 300 RPM. Which may have been the only problem in that old thread you posted in. He too replaced triggers, stator, and switchboxes, THEN the starter.

Once you know the motor is cranking fast enough, THEN DVA test the stator and triggers, IF they both pass then suspicion falls on the switchboxes.

Right now the only thing you need buy is a couple tools and piece of sandpaper to clean all battery cables. Then maybe disassemble and clean the starter. then a DVA meter to begin testing.

Not really wanting to get on your case, just trying to save you a bunch of money.

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

You seem to be in a big hurry to spend a LOT of money on ignition parts that you may NOT need.

The whole purpose of troubleshooting is testing to determine exactly what went wrong so that you only spend what you NEED.

The very first thing you need to test is for spark. A good battery, fully charged, with CLEAN connections on EVERY cable end is necessary to provide the starter the current needed to turn the motor over above the MINIMUM CRANKING speed of 300 RPM. Which may have been the only problem in that old thread you posted in. He too replaced triggers, stator, and switchboxes, THEN the starter.

Once you know the motor is cranking fast enough, THEN DVA test the stator and triggers, IF they both pass then suspicion falls on the switchboxes.

Right now the only thing you need buy is a couple tools and piece of sandpaper to clean all battery cables. Then maybe disassemble and clean the starter. then a DVA meter to begin testing.

Not really wanting to get on your case, just trying to save you a bunch of money.

I replaced the stator and it fired right up! Now the tilt goes up but won't go down! What could that be?

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

I replaced the stator and it fired right up! Now the tilt goes up but won't go down! What could that be?

 

[CharlieB]

Re: Mercury 150 xr4 no spark. Any thoughts?

That depends on which style trim pump is used. There is a two wire and a three wire.

One system uses two solenoids that look exactly like the starter solenoid, while the three wire uses two of the Bosch style relalys.

Later models are the Bosch style relay and a three wire motor. If it is this style, switch the relays and see if it will go down but not up. If that happens then one of those relays has bad contacts inside. This system both relays have the NC connected to ground. Both of the Blue and Green wires from the motor are grounded until one relay triggers and switches its wire to 12V and the motor runs one direction. So when the other relay triggers polarity is reversed, the other relay connects the other wire to 12V while the non-triggering relay remains to ground.

 

[Dukedog]

Re: Mercury 150 xr4 no spark. Any thoughts?

XR4 has tha three wire two solenoids stuff........Check tha solenoid with tha green wire. Make sure it pulls in or "clicks" when ya hit tha down button putting 12 volts on tha no. 10 green wire .......

 

[sam am I]

Re: Mercury 150 xr4 no spark. Any thoughts?

See imaged below for/if "Three Wire" setup with no response from switches.

Ensure 12V is present(and stays present during following tests) at down solenoid(j)'s red wire STUD (not ring lug), If trim motor is going up, then it and ground(shared) are properly good but check/monitor it's 12V anyway.......Ring lugs can be/get flaky even at the crimp sometimes eh?

Do test #1 first,

Test #1
Goes down?
Yes.......if it goes down, proceed to #2.
No........motor/motor wiring

Test #2
Goes down?
Yes......check 12V feeds to either the engine cowl switch(g)(and fuse "e" if equipped) and/or trim switch(d)
No........check solenoid's coil ground wire, if good.......*Replace Solenoid

***Solenoid's coil typically open if no "click" is heard during this test or Solenoid's contacts typically bad/burn't if "click" is heard during this test***



All JMO of course :lol:

I best go hang a motor, ice out smallies are call'n me........:fish2:

 

[1nebel0]

Re: Mercury 150 xr4 no spark. Any thoughts?

Simple test is to swap the solenoids and if it now goes down and not up it is the solenoids.. if not you got wiring issues that have nothing to do with the stator you replaced.....

 

[CharlieB]

Re: Mercury 150 xr4 no spark. Any thoughts?

If the motor runs at all it is good, as the relays simply reverse polarity to reverse the motor.

BOTH solenoids use the NC terminal to ground BOTH the G and B wires from the motor.

When either relay switches its wire, G or B, that then connects to 12V to the motor while the other NON-triggered relay provides the ground.

If it goes Up but not down, replace the UP relay as the NC contacts in it are failing to ground when the Down relay is triggered.

 

[sam am I]

Re: Mercury 150 xr4 no spark. Any thoughts?

If the motor runs at all it is good, as the relays simply reverse polarity to reverse the motor.

BOTH solenoids use the NC terminal to ground BOTH the G and B wires from the motor.

When either relay switches its wire, G or B, that then connects to 12V to the motor while the other NON-triggered relay provides the ground.

If it goes Up but not down, replace the UP relay as the NC contacts in it are failing to ground when the Down relay is triggered.

The "three wire" solenoid (not relay) setups (Duke and I's path, this is his setup we believe)doesn't use/have NC contacts, solenoids here(Merc uses in these setups) are just SPST contactors if you will. (Two different monsters, the other setup using grounded NC's(H-Bridge Config), is the "two wire" setup and that uses SPDT relays...yes, see below schematic)

In this case though, the un-energized solenoid (Grn or Blue wire, which ever case) floats/is open while the other energized solenoid completes/switches 12V(Red wire to Grn or Blue wire, which ever case) to the always hard grounded motor(the motor's windings are center tapped to ground)....see above schematic(motor's blk return wire goes to mounting bolt of solenoid).



Yes, I know, this schematic calls the relays "solenoids" as well........We have the NSA hunting for the tech writer that did that. And yes, I'm aware that there are solenoids and contactors out there with NC contacts which are SPDT........We're'll(we are all) forced to use the term "condenser" too!! I just go with it anymore.

The terms "two wire" verses "three wire" is the real meat here though eh?

 

[sam am I]

Re: Mercury 150 xr4 no spark. Any thoughts?

...

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

See imaged below for/if "Three Wire" setup with no response from switches.

Ensure 12V is present(and stays present during following tests) at down solenoid(j)'s red wire STUD (not ring lug), If trim motor is going up, then it and ground(shared) are properly good but check/monitor it's 12V anyway.......Ring lugs can be/get flaky even at the crimp sometimes eh?

Do test #1 first,

Test #1
Goes down?
Yes.......if it goes down, proceed to #2.
No........motor/motor wiring

Test #2
Goes down?
Yes......check 12V feeds to either the engine cowl switch(g)(and fuse "e" if equipped) and/or trim switch(d)
No........check solenoid's coil ground wire, if good.......*Replace Solenoid

***Solenoid's coil typically open if no "click" is heard during this test or Solenoid's contacts typically bad/burn't if "click" is heard during this test***

View attachment 228467

All JMO of course :lol:

I best go hang a motor, ice out smallies are call'n me........:fish2:

Thanks gonna have a go at fixing it on wednesday!

 

[travisb5470]

Re: Mercury 150 xr4 no spark. Any thoughts?

Thanks gonna have a go at fixing it on wednesday!