Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

[achilles555]

I have a 1988 Mercury XR4 150. I've got her running great - but there's one last problem I can't get figured out. When I get past about 1/4 throttle, my Oil Injection Alarm starts beep - beep - beep, and won't stop until I slow the boat down to about 1/4 throttle again. It's not a constant beep, so it's not overheating. It's definitely the oil. I've replaced the sending unit, made sure that my reserve tank was full to the top, and checked both oil tanks and caps for cracks or leaks. I've also pulled the oil pump off, and inspected it for problems. Everything looks good. What's got me buffaloed is that it only starts beeping at the higher RPM's. Anyone out there have any suggestions? Thanks for the help. AC.

 

[j_martin]

Re: Low Oil / Oil Injection Alarm at High RPM's

Re: Low Oil / Oil Injection Alarm at High RPM's

There's a wire going from the oil alert module to one of the coil wires on the switchboxes. Move that wire to any coil terminal on the other switch box.

I'm guessing you aren't getting coil pulses to the alarm module, and it's setting it off. High speed switchbox or stator problem. The move I described should sidestep either one.

A little theory here, the alarm module looks for a pulse train from the switchbox, and also one from the motion sensor. If one is missing, it alarms. If both are there, or both are missing, it doesn't alarm. An additional alarm signal is the level switch in the motor tank.

hope it helps
John

 

[achilles555]

Re: Low Oil / Oil Injection Alarm at High RPM's

Re: Low Oil / Oil Injection Alarm at High RPM's

thanks john. i'll try that. from my research, that wire is tied to the number 2 cylinder. if i move it, will that cause any problems? will the warning system still work? thanks so much. you've been a huge help. ac.

my switchboxes should be good, i just replaced both.

fyi - with the newest switchbox in place, my xr4 is running like a scalded dog. it's amazing!

 

[achilles555]

Low Oil / Oil Injection Alarm at High RPM's - UPDATE

Low Oil / Oil Injection Alarm at High RPM's - UPDATE

j_martin - you're a genius. I started out this morning by replacing the sensor module and bearing. I thought that had to be it for sure. No luck. Same beeping. My last thing to try before disconnecting the whole thing was your suggestion about switching the switch box wire from number 2 cylinder to another cylinder on the OTHER switchbox.

I did as you suggested...and sure enough, the beeping completely stopped at the higher RPM's. I'm not 100% sure what that means. Maybe a new stator? I need to find out. It's great to know that I'm on the right track, though.

It does still beep a little, but only at about 1/2 throttle. It beeps a couple of times, then stops.

If I run the boat this way for a while, is it going to hurt anything? Also, what should my next course of action be? A new stator? Thanks so much for your help with this XR4. I hope I can return the favor someday. AC.

 

[j_martin]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

Your next course of action should be to investigate both the stator and the trigger outputs with a DVA. There is no other reliable way to do it. A dva, or dva adapter is much cheaper than any part you'd replace, so consider it an investment.

There's a troubleshooting chart for ignition that should track it down to what's wrong. By properly executing the troubleshooting procedure, you can get right to the bad part, and not waste any time or money.

You have a bad stator, or trigger, or switchbox, or coil, or a combination. The oil alarm was not seeing the pulses from the ignition circuit it was looking for. That's all you know at this point.

It must be running poorly. Fixing it should improve performance significantly.

If it's running real strong, and you're sure there is no misfire, the oil alert module might be marginal. Never heard of that, though. The XR4, right out of the box, is about 162 prop horses at 5800 rpm. That and a skinny lower, and it should run like a scalded dog, or better.

I wouldn't run it that way. Misfires, especially if they are poorly timed, can cost you major powerhead damage.

hope it helps
John

 

[achilles555]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

hi john. it seems to be running strong, but since this is a new boat (to me), i have nothing to judge it against. i don't want to mess-up the powerhead, so that leads me to my next point.

i looked at the manual and found the step-by-step process for testing the ignition. it didn't look too bad, until i started reading. from what i can tell, it's WAY over my head. for example: i need a dva, a dva adapter, and possibly an ohm meter. i can do most of my testing with the ohm meter, but the stator and switch boxes can't be tested without the adapter? i don't even know the difference between those three things (dva, dva adapter, and ohm meter). and on top of that, the old ohm meter that i have has so many different settings and places to put the probes...i have no idea what i'm doing.

as much as i hate to do it, i guess i'm going to have to take it to the local marina. at $75 an hour, i hope they can figure it out pretty quickly.

If you have any pointers that may make the testing process seem a little less overwhelming, i'm all ears. like i said, i have the mercury service manual for this motor, but when it gets to the electronics...it's all greek to me.

 

[achilles555]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

ok john. after looking at some of your past posts, i think i'm familiar with the difference between the test equipment. the most important thing i need is the voltmeter. that will allow me to test both voltage and ohms. the dva "direct voltage adapter" is an adapter that works with my voltmeter to test lower voltages/ohms that my voltmeter wouldn't normally see.

in your opinion, can i get by with a voltmeter for the stator, trigger, etc. for now, or do i need the dva to start with? i found a couple voltmeters with the DVA built in on eBay for about $130, or i could buy the original Mercury one for about $100 online. suggestions?

one other question. as i was looking through the different tests for the stator, trigger, switchboxes, etc. the manual gives precise test data, but it doesn't indicate whether the motor should be running at idle, or not running at all, or if i should use a remote starter to turn the engine while taking the readings? unless i'm missing something, it's pretty unclear just HOW to perform these tests.

thanks again for the help. ac.

 

[j_martin]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

What a DVA is is a peak reading circuit in front of an ordinary voltmeter. You can make your own adapter if you wish. The only "standard" reading that would make any sense is the stator power output, which has nothing to do with the ignition on that engine, so it doesn't help.

An ohmmeter, which is a function on most multimeters, tests the resistance of a circuit. It will easily find grossly shorted or open coils, or diodes, etc.

To give you an idea of the value of the correct instrument. A DVA meter test on the coil terminal of the switchbox that feeds the oil alert module will instantly tell you if it's good. If it is, the module's bad, you're done troubleshooting. With parts that go for 100's new, and even pretty high bucks this time of year used, it's worth while to get the right instruments and determine the problem in one or two passes.

hope it helps
John

 

[achilles555]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

hi john. i'd be interested in making my own adapter. do you know of any links that could walk me through the process of creating one?

thanks again for the help. ac.

 

[j_martin]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

http://forums.screamandfly.com/forums/showthread.php?t=32159

 

[hkeiner]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

I'd be interested in making my own adapter.

Others may disagree, but I suggest that it is better to suck it up and buy a DVA meter. It is just easier to use. As a newbie, I once considered making my own DVA adapter but I concluded that I could not understand the available instructions well enough to avoid probably constructing the adapter wrong or avoid incorrectly interpreting the readings using an adapter on a standard volt meter. As previously mentioned in this thread, the cost of a DVA meter is not that much considering the saved time and cost of not replacing good electrical parts or the frustration of not figuring out what electrical part is actually bad.

Just my thoughts....

 

[achilles555]

Re: Low Oil / Oil Injection Alarm at High RPM's - UPDATE -

Thanks for the info, guys. I found a reasonably priced DVA Voltmeter on eBay:

http://cgi.ebay.com/ebaymotors/ws/e...E:B:EOIBSAA:US:11&viewitem=&item=300221817343

Cost was $70 shipped. As much as I didn't want to, I guess I'm going to be learning a lot about the ignition and electrical system of my Merc in the next several days. As soon as I get the multimeter, I'll run some tests and report back my findings. I may need some help here and there along the way, but at least I know where to come for some help. You guys are the best. AC.