Merc Optimax Timing Problem

[Tuna]

I have a sick (demented?) 2001 200 HP Merc Optimax. Less than a year old and it is causing me major grief. I was wondering if anyone has had a similar problem and, if so, how they fared.

After a few months of use in 2001 (and after several recall repairs), I had an issue where the engine would sound sick between 3000 and 4000 rpm, drop as many as 200 rpm, and eventually not be able to exceed 3000 rpm. Mechanic could not reproduce, and it ran OK for the rest of the season (althogh always had a bit of a problem between 3000 and 3400 rpm and couldn't run in this range).

This season, the issue is much worse.

First trip out, engine would not exceed 2800 rpm.

Mechanic could not reproduce later in week.

Next trip, engine would go higher, but it would slip 200-400 rpm frequently and sounded ugly.

Mechanic could not reproduce later in week.

Next trip, engine would not go higher than 2800 rpm and sounded sick above 2400. Called mechanic while on the water, went back and showed him. He noticed my temp gage showed engine running too cool, saw what he thought was a problem with the thermastat, said the plugs were fouled. Didn't have plugs that day, but replaced the thermastat. Temperature gage still showed it running cool, although engine was not (mechanic questioned where sensor had been placed, thinks cool temp gage misleading).

Got plugs next day. Went out with mechanic - boat ran well for a few minutes at 45 mph, but when I brought to 3000 to 4000 range, engine sounded bad, dropped 100 rpm here and there. I could live with that if replacing thermstat kept plugs from fouling...

... but it didn't. Took boat out myself and within 5 minutes it was slipping rpm regularly, and within a half hour looks like plugs were fouled again and couldn't get past 2600 rpm.

Mechanic off weekend - one day boat continued to run at top of 2400, next day it just randomly jumped from 2400 to 4000, then started losing rpm, then went back to 2400 max.

I get the feeling when I am running at 2400 rpm, when it is max speed, that more fuel is being pumped than burned. Looked that way from how much gas I used, and fact that one day, while at 2400 rpm, engine jumped back to 4000.

Anyone ever hear of a problem like this? If so, anyone ever resolve (without replacing the evil Mr. Merc?).

[Tuna]

Interim update (in case anyone experiences something similar).

Diagnostics found nothing and mechanic, working with Merc tech support, through process of elimination, believes problem is 3 bad injectors. Should find out later this week after receipt, install and checkout.

[Tuna]

Got one day on the water after the fuel injectors were installed. Although engine did not revert to not being able to run over 2X00 rpm, it did lose and regain from 50 to 800 rpm randomly (which previously led to the 2X00 limit). Called Optimax hotline today to see if they would claim this normal or acceptable operation (on another website, someone with same problem was told by mechanic that was OK). Merc said no, that's not normal or acceptable. However, despite the many attempts to fix this, Merc is not yet willing to consider replacing the engine. I've got to keep taking them up on the "we'll make this work" some more before they will consider replacing it.

Merc's on the edge of having a very pleased client (if they can make it work or replace it and replacement works) or lifetime irrational Merc basher. Wonder how long I will stay on the edge.

[Tuna]

(God forbid this thread be relevant to anyone else but me)

OK, lets try a new ECU (my third I believe, although I am in the process of verifying my 8/2001 recall warranty work). Will have a chance to see if this helps this weekend, assuming the part arrives on time.

Two positive things have happened since last post:

1) Some of my best songs I write in moments of crisis. Not really versed in country music, but I have a start of a new song ("My Merc don't work, its a welfare engine"), sung with a twang. I have a few verses but may change them as I work the instrumental parts.

2) The owner of the marina stuck with the work has realized he will never recoop his efforts from Merc on this, so if the new ECU does not do the trick, he's calling Merc on site. Merc never replaces the welfare Optimax's until this happens.

[Tuna]

'Nother update.

Mechanic has reported some improvement from new ECU but also noticed some issue with Throttle Position Indicator so ordered some more parts, maybe will make it on engine today. (I've seen posts on other boards where TPI contributed to this problem, so sounds like its worth a try here too). If it gets on engine today I will try boat out Saturday.

Would love to eat my words (that the motor I have is a lemon). Will update again after more info.

[Tuna]

Last post (unless problem or related problem reappears).

Looks like the last few changes made a lot of positive difference (my gut says the TPI change was the key one). Only went out for about 4 hours Saturday, but engine performed acceptably - a few rpm shuffles, but generally holding speeds.

As long as it runs like it did Saturday, I would consider it fixed.

Now to put some serious hours on the engine.

(Many thanks Matt [mechanic]).

[Mark Cahill]

poorly running engines don't inspire confidence.

Hope you get a ton of hours on it soon!

[tmillerzzz]

Tuna

Hows it running?

[Chap]

Hello,
Murcurypro may be able to help over at boatsetup.com

One of his posts.

http://www.boatsetup.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=4&t=000256

Thanks
Chap

[Tuna]

Thanks for the link - I now have a large pile of similar reports from various websites.

Hmm, was not going to post an update until I was certain which way I was heading, but I seem to be deciding that so...

Since the last set of changes to my engine, the rpm shuffle has increased with each use. So has the incredibly sick sound of the engine when it drops rpm (sounds better when it gains rpms). So has the size of the rpm gain or loss (not as often as at its worst, but a few up to 1000 rpm). During my last day on the boat, I also noticed the beginning of an rpm restriction - not the absurd low 2400 rpm limit [although I will not be surprised to get there soon] but at one point last Saturday I could not get the engine over 4000 rpm (it should go to 5000).

I was fishing with Josh Reibel, who posts here and used to write the NY/NJ fishwire a while back. It was a dog of a day (although he caught a rod I had lost the day before, which was a nice stroke of luck), and we moved the boat around quite a bit looking for real fishing action.

He noticed that my worst rpm range, 3000 to 4000, is the range one would normally want to use on such trips.

Anyway, today I faxed a letter to Office of the President at Mercury Marine which is what the Optimax hotline said I needed to do if I wanted to get more attention, or the possible consideration of a replaced engine. In it I said that even if the old 2400 rpm restriction does not recur, the engine is not safe, as the large random rpm changes could cause an accident, particularly at Montauk in the fall when conditions can be extreme.

I may change my mind based on the next few weeks, but, if as I suspect, the engine continues to deteriorate I will be planning on having a different engine on the back of the boat before the start of the albie run at Montauk. My hope, of course, is that it is a functioning Optimax, as my alternatives are expensive. It might even have the same serial number as my current engine, but with the number of parts that have been replaced, if it really gets fixed, I would consider it a different engine than the one I have today.

Will update again later.

[AndyF]

The only problem I ever had with my Yamaha was a loss of rpm similar to what you describe (maybe not as bad). Apparently, Yamaha had a problem with their oxygen filters and I'm told Merc may use the same one. You might want to ask one of the mechanics if that could be a source of the problem. They replaced the censor at little cost last year and it now runs as good as new.

Good luck. You should definitely demand satisfaction from your dealer and/or Merc considering how new your engine is. (If you do replace it, though, the Yamaha four-stroke sounds excellent and I'm told it's very quiet, and my Saltwater series has run flawlessly with the exception noted above).

[Tuna]

How about a smaller prop?

My conversations with Merc as a result of my letter to the offiice of the president were a bit frustrating. I wanted an answer to a simple question - how many unseccesful attempts to fix the engine before a refund or replacement? Merc would not answer this, but said first step before even considering would be to have Merc come on site and try to fix.

Well, Merc didn't show on site but have asked mechanic to make one more change before considering on site visit - smaller prop. Max rpm on the engine has never been much over 5000 (maybe it hit 5200 once or twice when it wasn't evil). Merc says it should be as much as 5700. Theory - prop too big.

Although it sounds a bit crazy, I have noticed that folks who know their boats spend a lot of attention on the prop.

But should this not do it, I have an answer to Merc's unwillingness to state clearly how many more unsuccessful attempts I will live through - the answer is 3 (I'm already at 4) according to the Magnuson-Moss Warranty Act (which, unlike the Lemon Law of NY, does cover boats and their engines).

Hmm, a smaller prop. Heck, who knows?

[Tuna]

Smaller prop makes engine sound less sick getting on a plane, but had zero effect on problem. Engine still changes rpm randomly between 3 and 4 thousand rpm, and generally gets worse throughout day.

[Tuna]

Merc TAM was on site yesterday.

Rebuilt fuel pump but no joy.

Although diagnostics did not indicate problem, a new MAP sensor is being sent for the next try. Hope to see effect by this weekend.

[Tuna]

Merc TAM went on site again Friday, Aug 2.

New map sensor did not fix issue.

However, according to marina mechanic, TAM then started replacing more parts like crazy. On next test, engine held rpm. Marina mechanic then insisted on changing parts back to original one by one to see which one did the trick. He thinks it was the coil to the two lowest cylnders (which DDT did not spot).

Put more than 6 hours on the water Saturday and except for a brief glitch at start of trip, engine would hold any rpm level chosen. Looks fixed.

Need to put some more hours on the water. Will only post again if issue resurfaces.

PS: Merc corporate told me last week that the TAM was their very best field mechanic - good thing, as marina mechanic told me TAM found my engine problem the most challenging he has faced.