01' 200 Merc Optimax random shutdown?

[galvetraz302]

Got the motor w/ boat a few months back. Replaced water pump, changed plugs, drained fuel tank, checked compression, everything else checked out. When we ran out to the Buckaneer fields last monday everything went smooth. On the way back in about 20 miles out the motor was running @ about 4600 rpm and it just shut off. I turned the key to off position and then restarted no problem. Then I was running in @ about 4000 rpm about 9 miles out the motor shut off again. Turned key off then started back up again no problem. So we figured the PCM was loosing power and it might be a ground. Sat. we pulled the ground bar and cleaned all corrosion and replaced all ground connections. Took the boat out yesterday and as soon as we cleared the dike @ about 4500 rpm the motor shut off again? Then started no problem. Ran off Bolivar the rest of the day from 3300 rpm to 4000 rpm and the motor ran like a champ. I assume the problem is when I run @ higher RPM? Has anyone had this problem before? Does it sound like a problem with the wiring harness, or could the PCM be going out?

Any help appreciated.

 

[sdsaw]

Re: 01' 200 Merc Optimax random shutdown?

I don't have the same motor but had similar shut down or a quick off/on issues.
Dealer tried several different fixes to cure the problem with no avail. We finally replaced the main relay which ended up being the culprit.

My best guess as to what was happening was:
As the motor got warmer it would hit a temperature(about 15 minutes after start up) which caused the relay to lose momentary contact which caused the motor to stumble(almost like turning the key off then on real quick) or it would just die but restart easily.
After the motor got hotter it would run all day without missing a beat.
I don't know if you use the same relay but our motors are of similar vintage. I also have one of those Merc's with a Yamaha powerhead in it so I may also have a Yamaha relay.
But definitely keep this in mind while you troubleshoot your problem.

Good Luck, Scott

 

[galvetraz302]

Re: 01' 200 Merc Optimax random shutdown?

Thanks Scott, I will take a look at it.

Tonight we went over the wiring harness and all the connections everything looked great. Had one guy tell me it may be a bad computer? I guess this is possible? How common is a computer failure?

B

 

[sdsaw]

Re: 01' 200 Merc Optimax random shutdown?

The question is: How expensive is a computer? If you have to buy one just to see if it helps and it doesn't, it's wasted money. If you can get a known good loaner to try, that would be ideal.
I posted about the relay because my mechanic tried all the usual suspects to cure my problem including a new computer to no avail.
He, along with the factory techs were just scratching their heads as to what could be wrong. Since they tried everything that they thought it could be, I suggested to try the relay since it felt like a electrical problem. To everyone's surprise including mine it was the relay!
All the repairs and parts changing was covered under warranty so it wasn't too painful but was a pain taking it back for repairs and then go do a on-the-water test which took around 2 months to finally figure it out.
If you are not under warranty, you want to find the problem ASAP so your wallet doesn't get too thin
I'm not saying that you have a defective but it is, it cost a lot less than a new computer.
Check back here and I'll post what brand relay that's on my motor (I think it's a Japanese brand)
Scott

 

[sdsaw]

Re: Brand of Relay

Re: Brand of Relay

OK, I checked for a brand name on my relay and did not see one printed on it.
There is a part # only and this is it:

SN2210
5J06

I'm all tapped out on my knowledge of your problem.
It would be nice and possibly beneficial to somebody else if you post what was causing your issues.

Good luck, Scott