Pontoon Boat & Deck Boat Forum

I know this is more 'engine' related than 'pontoon' related, but....

We recently bought a new Harris CX 240 w/ a 150 Mercury OptiMax. On about our 8th or 9th time out (once or twice a weekend for a couple months), the motor would not turn over when we went to take it out. We thought we had somehow killed the battery (although it did not sound that weak) and had the shop come out to check the battery out and charge, if necessary (the shop owns the marina we are in). Long story short, they discovered the motor was hydro locked w/ water in the NO. 4 cylinder.

They took the boat/engine back to their shop and could find no obvious reason for the hydro lock. Since it was evidenced as we tried to start it, they said it must have happened right as we docked and shut down. We had not 'chop throttled' in any way, shape or form, nor done any kind of James Bond maneuvers. The shop changed the oil, replaced the plugs, and had the boat back in the water. No damage was done (to starter or to cam/rods, etc). Mercury sent a rep out to look at it, saying that they have never had this happen to an OptiMax before. They took it out on the lake and tried to replicate the hyrdolock by performing various aggressive chopping maneuvers,etc. No luck.

Anyway, the odd part - when we took it out the next time, the engine was about 1/2 as loud and ran at a slightly different pitch (much more pleasant). I had heard that the 4-strokes were quieter, but having never owned one, did not know what to expect. It seems to me that there was something wrong with the boat when we received it, but I am not sure what that might have been. Anyone have anything even remotely similar or want to hazard a guess?

Trainwreck20 wrote:Anyway, the odd part - when we took it out the next time, the engine was about 1/2 as loud and ran at a slightly different pitch (much more pleasant). I had heard that the 4-strokes were quieter, but having never owned one, did not know what to expect. It seems to me that there was something wrong with the boat when we received it, but I am not sure what that might have been. Anyone have anything even remotely similar or want to hazard a guess?

Optimax are 2 stroke Direct Fuel Injection
About OptiMax -- Not Your Typical Two-Stroke (Mercury Website)

Weird about the hydrolock.

Now this is probably completely unrelated but my Optimax had an issue this Spring/Summer where water leaked through the 2 stroke fill hole in the cowl and into the 2 stroke oil holding tank and then it was pumped into the engine. Water where 2 stroke oil should be is bad long term. But in my case, that is how water got into my motor and burned out number 1 cylinder and caused me to have to get a new powerhead.

-ron

I hate to say this but, motor's don't fix them selves. You should keep a close watch on it, and listen for any change in the motor sound when under way. Because it will most likely happen again. listen carefully when starting it, and if it acts like the last time STOP trying to start it as you can bend a rod or crack a piston. How did they determine you didn't have a bent rod? You stated the motor sounds different now, so I would be suspicious, that you did do some type of internal damage. I hope it's still under warranty? Does it perform as well as it did before, are the RPM's at WOT still the same?

First off, sorry, I meant Mercury Verado 150, was not paying attention when I was typing it and had been searching hydrolock issues and mercury all morning .

How did they determine you didn't have a bent rod?

The service center dry docked the boat and pretty much went over every part of the motor, specifically to check for bent rod or other 'typcial' hydrolock complications. I don't know what they specifically do to ensure that there is not some minute damage done, though.

STOP trying to start it as you can bend a rod or crack a piston.

We did not try to start it but a couple times (fortunately) before we decided that it might not be the battery. Apparently, the fact that the motor was not actually running when it locked probably prevented any damage from being done.

You stated the motor sounds different now, so I would be suspicious, that you did do some type of internal damage. I hope it's still under warranty? Does it perform as well as it did before, are the RPM's at WOT still the same?

The motor definitely sounds different, but much 'better'. The RPMs/Speed/throttle all seem to match up to where they were before (it is hard to really say exactly). As for warranty, hydrolock is not covered under Mercury warranty; however, we do have correspondence indicating that damage (if any is found) would be covered. Mercury does seem to be genuinely baffled and concerned since the Verado is a newer model engine.

I have a suspicion that there may have been water in the oil that was making its way into the cylinder (they did find water in the oil, but that is typical in hyrdolock, but with water going from the cylinder to the oil, not the oil to the cylinder). A very small amount of water in the cylinder could explain the different pitch and also possibly allow the boat to run while hot with a little water in the cylinder but then freeze up when the engine is cool. This would require a very slow increase in the water in the cylinder until that exact balance is reached. I am not sure this is possible (I am not a motor specialist by any stretch), but it is better than any explanation they have been able to give me.

I have heard of water backing in to the lower cylinders on the Verados, through the exhaust. If the motor is ran to low in the water, or backed off the throttle to quickly and let the water back splash into it.
The man to ask is Glen at http://www.veradoclub.com/ if anyone has an idea, he will. He has helped me out several times as I become more aquainted with my Verado. So many times, that I became a sponser of his website.
Give him a try!
Good Luck..........Bryan