Mercrusier 5.7

[jlockwood]

I have a 1987 Bayliner with Mercruiser 5.7 engine.Last week I was pulling into the dock and lost power and stalled. I started it up again. There was a distinctive valve knock. I shut it down and had the marine mechanic look at it. He telling me I have a valve that is bad. That they will need to pull the engine and replace the engine or try to rebuild the engine. What kine of money am I looking at?

 

[tommays]

Re: Mercrusier 5.7

did the motor get water in it when it stalled ??<br /><br />its strange for it to go from ok to shot in any other way<br /><br />is the boat used in fresh or salt water and is it raw of fresh water cooled<br /><br />with the rust and such from 1987 a lot of people find it better to go with a compleat new crate engine rather than trying to rebuild and use the good electric parts from the old motor<br /><br />no mater what you do your looking at over 6000 dollars<br /><br /> a good shop will not resuse your manifolds and elbows its to easy for them to ruin a new motor<br /><br />you should also take a good look at the over all condition of the hull for any rot or other problems before makeing a big investment in repowering<br /><br />tommays

 

[waterone1@aol.com]

Re: Mercrusier 5.7

How many hours are on the engine ? Salt or freshwater ? Closed or raw water cooled ? Was there any sign of water intrusion in the cylinders?

 

[wvit100]

Re: Mercrusier 5.7

If it is just a bad valve then you can probably have the heads redone. Nowhere near $6000. Why did the mechanic say you needed the engine rebuilt? Was it burning oil or anything prior to the problem?

 

[jlockwood]

Re: Mercrusier 5.7

The engine is used in Freshwater. The engine was not burning oil. The mechanic feels the engine was put under stress. (ie overloaded) Which I can tell you did not happen the most people I ever had on the boat was six and never pulled a skier. He went on to say he felt the valve was "dafadiled" . There is still compression in the engine. There was no sign of water in the cylinders. The system is freshwater cooled. I have found a price for e rebuilt at $ 1700.00. The marine quoted me a price of $ 1900.00 with installtion total cost of $ 3200.00. I am not sure how to proceed. The boat is out of the water for the winter and the marina is getting ready to shrink wrap it. So I need to make a decision pretty soon on what to do.

 

[wvit100]

Re: Mercrusier 5.7

"dafadiled" - What does that mean? If this is the best description your mechanic can give you then you need to get another opinion. If it still has good compression in all the cylinders then the valves are OK. There are a lot of reasons a motor could loose power and stall besides a valve, a valve sound would be more of a clicking or tapping sound a loud knocking sound is what a bearing sounds like.

 

[Don S]

Re: Mercrusier 5.7

He went on to say he felt the valve was "dafadiled"

Hopefully he called it a "tuliped valve".<br /><br />If a bad valve is the only problem, then either replace the valve and have the seat reground or replace the head if the seat is gone also. No need to replace the complete engine for a head problem. When a valve is tuliped, it does not make contact with the seat and there is no compression on that cylinder.<br />The engine may have been overloaded due to prop size. Were you able to get between 4400 and 4800 rpm at Wide Open Throttle? if the rpm is too low at WOT, then you are overloading the engine. because you are over proped.

 

[waterone1@aol.com]

Re: Mercrusier 5.7

Now that we know that it is a freshwater engine, we can rule out replacing the engine. How many hours are on it ? In my opinion, if it has less than 1000 hours, I would just have valve work done. More than 1000 hours and this could be time to do a complete rebuild.

 

[kdmiller8251]

Re: Mercrusier 5.7

New engine?? I think not... Like the others said.... You can have the top half rebuilt, if its not that old and it didnt do anything to the piston.... You can buy a reman engine (long Block for 2.5K, and find someone to install or do it your self for around 1000.. If you pay around 6k you are nuts...<br /><br />I would go get a 2nd opinon on that motor before doing anything. sounds like your mech is lookin for the easy way out. <br /><br />Dont rush anything, you got all winter to figure it out.... Shrink wrapping is cheap compared to having a new motor put in....

 

[Bondo]

Re: Mercrusier 5.7

I Agree with all the above........<br /><br />Find Another Mechanic........<br /><br />Your Tech is a Thief........

 

[jlockwood]

Re: Mercrusier 5.7

I have a mechanic that will work on the boat at my house. He suggested waiting until March to move it here. Thank you for your advice