merc 140 problems

[travis46815]

I have a merc 140 in the boat I recently purchased. I took it out for a ride and the trouble started. It started up no problem. I went to put it in forward and it stalled. I got it in forward by 'feathering' it in and was underway. When I went to give it some throttle the boat never picked up rpm or went any faster. I put it in neutral, and hit the throttle and the rpm gauge went right up. I noticed a knock when idling, that went away as the rpms increased. Also noticed some water in the oil, but it didn't get any worse and it wasn't very much over full. Changed the plugs and took it to the mechanic. He hasn't had a chance to look at it yet, but does anyone have any idea what I may be in for?

 

[Rocky_Road]

Re: merc 140 problems

I have one boat with this engine, and they are famous for 'eating' head gaskets.

My guess is that your mechanic will be telling you this....

The real question will be "why"? In my case, it overheated just once. My heat exchanger was bad and leaked anti-freeze until it was too low.

Be sure that you have left it with someone that fully understands that engine, and knows where to look.

Happy boating!

 

[travis46815]

Re: merc 140 problems

I hope it is just a blown gasket and not problems with the block. The temp never went above 140 for the hour that I played with it while it was running, and never took any more water en the block. Would the motor have a knock to it if it were head gasket problems? Could the timing be out bad enough to cause a knock in the engine?

 

[Rocky_Road]

Re: merc 140 problems

I hope it is just a blown gasket and not problems with the block. The temp never went above 140 for the hour that I played with it while it was running, and never took any more water en the block. Would the motor have a knock to it if it were head gasket problems? Could the timing be out bad enough to cause a knock in the engine?

The "knock" that you heard could be the engine hydro-locking with the introduction of water/antifreeze into the cylinder(s). That is what mine did.

Like I said...just make sure that your wrench puller knows this engine. It is an older vintage, and when properly maintained a real work-horse! But it has it's idiosyncrasies, and it is the 'kiss of death' if it is allowed to overheat.

Happy boating!

 

[Rocky_Road]

Re: merc 140 problems

I want to apologize to you for mistaking your engine for my older 470 engine...you won't have the same issues that my 470 has. I should have paid more attention to your opening post....

I am sure that some 140 owners will be here soon to help you (and 'flame' me!).

My bad....

 

[travis46815]

Re: merc 140 problems

no problem. Thanks for the help anyways.

 

[Bondo]

Re: merc 140 problems

Could the timing be out bad enough to cause a knock in the engine?

Nope, not at Idle....

It sounds like you've got multipule issues going on,...
A competent Mechanic should be able to diagnose how bad or good it is...
A Full Tune Up,+ Service probably is a Great place to start...

 

[fat fanny]

Re: merc 140 problems

A couple of simple troubleshooting techniques you could have used before toating it off to the wrench is too buy a harbor frieght compression gauge and while you were changing plugs you could have checked your compression #'s most likely you have a blown head gasket my 3.0LX has gone through 2 of them in the last 3 years and the symptoms are all to clear sounds great on muffs and as soon as power is added it eighter dies and moans then stalls and has a hard time to keep running. I do not want to be the barer of bad news but that is probably it. Go up to the adults only section @ the top of this forum and download the manual to your engine and read it as well as all the other valuable info before you see your wrench on his diagnosis so you have some sort of knowledge of your engines symptoms.

 

[travis46815]

Re: merc 140 problems

Thanks for the info. Ill wait and see what he says. .