40 Magnum 4cyl; Zapping the diodes?

[stan_deezy]

Quick story: 1991 Mariner Magnum 4cyl goes into the shop to get the stator replaced due to non-starting problem.<br /><br />Shop fix that and phone to say the engine is ready but.........oil alarm was going off, they couldn't see anything wrong with the oil injection system, suspected it was just the alarm module (their words, not mine) and they had a trick that had fixed it <br /><br />Apparently the trick was to pass a current the wrong way through the module which "resets" the diodes <br /><br />Engine gets sold the next day and used one week later> buyer phones up very irate because the engine has thrown a conrod and is toast: no warning, no oil alarm nothing, as stated "the engine was great then blew up" <br /><br />Question: anyone ever heard of this "trick"?<br /><br />I suspect that what happened was that the module was fried to silence it and therefore gave no warning of non-oiling but I'd like to hear if anyone else has ever come across this fix before and try and understand why it would work?<br /><br />cheers for any replies and apologies if this in the wrong section

 

[Laddies]

Re: 40 Magnum 4cyl; Zapping the diodes?

There is no such service procdure, they simply burned the oil warning module up, but the other part of the problem is that the warning system only is for low oil not for pressure so that would not of sounded for the pump not working any way

 

[stan_deezy]

Re: 40 Magnum 4cyl; Zapping the diodes?

Thanks Laddies, of course. Yes I hadn't remembered that it's only a low oil warning device....stupid me!<br /><br />Thanks again. Been wracking my feeble brain trying to figure out why a perfectly good engine would throw a rod without any warning.

 

[Moody Blue]

Re: 40 Magnum 4cyl; Zapping the diodes?

When was the waterpump impeller last replaced? Might have overheated and ...... poof.<br /><br />Did the shop say it was the oil alarm? Could it have been the overheat alarm?<br />Get the shop to show you where in the factory manual it shows this magical "fix". Demand compensation and don't stop until you are satisfied then don't ever deal with that quack shop again.

 

[stan_deezy]

Re: 40 Magnum 4cyl; Zapping the diodes?

Cheers RodC, you are almost certainly correct about the waterpump, heres the full story:<br /><br />I had advertised the boat and it had been sold subject to delivery. I went to do a final test of everything on board and the main engine (the mariner 40) refused point blank to fire. A few checks later and I was stumped because I didn't have any test meters around. The shop took in the engine on the boat and replaced the stator. They mentioned the alarm and the "fix" they had carried out.<br />When I went to pick the boat up they showed me that the non-starting problem was cured by starting her up in the parking lot: no muffs or water I felt very uneasy about that but some people on the boards have assured me that the impellor should have been safe as it was only run for a minute and probably was still wet from being tested by the shop earlier.....<br />Anyway, the minute I get home I set up the test tank and run the engine for a good ten minutes to check the charge system, water flow etc. The alarm sounded briefly at "turn key" as it is supposed to and there was plenty of water.<br />Boat was delivered the next day to the new owners.<br />Then I get a phone call saying that twenty minutes into a WOT run the engine throws a rod and they are very unhappy (not surprisingly) and they wonder if it was anything that might have been done during the repair.......<br /><br />I'm still in two minds about this: the fix sounds like a real bodge to me and starting an engine without water was enough to scare me away fom the shop but I'm darned if I can figure out whether anything the shop did could have led to a great engine blowing itself to bits?<br /><br />The only other clue is that the new owners were desperate to hear the "new to them" engine and I had to explain several times about not starting it without plenty of water. I strongly suspect that they may have started it on the driveway and assumed if it "was only run for a few minutes it would be fine" not realising that they were "cooking" the impellor.

 

[Nos4r2]

Re: 40 Magnum 4cyl; Zapping the diodes?

Are they still giving you grief about that mate?<br /><br />In all honesty if they let their kids turn the auxiliary upside down like you said it sounds like they had absolutely no idea what they were doing anyway-blown warning module or not. Sometime's you've just got to say 'enough' to people.

 

[Scali]

Re: 40 Magnum 4cyl; Zapping the diodes?

I've put maybe 100 hours on my '94 Merc 40 4 banger, the oil warning module was fried when i got it & I never replaced it.<br />From my experience over the last 30 years of boating those system check type warning systems give off 10 false alarms to every 1.<br />I keep my eye on the oil level { & even run 100-1 premix } on top of my oil injection system ..<br />Keep an eye on the WP output, screw those things.