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57 engine problems

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bill_k

Regular Contributor
"after motor was un-winterized

"after motor was un-winterized and ran acouple of tanks of gas through it, the motor seems to be getting weaker also started to notice that there is some coolant on top of the motor. but can't seem to find where it is coming from if the exhaust is leaking would that affect the performance of the motor where it is very noticeable, new to this motor but have worked on many other boats that I have owned. what would be some good things to check out and how to check them on this motor. before I just take it to the dealer and let them tell me I need a new motor when it just needed a gasket or something, by the way the motor has about 400 hours on it.."
 
"Bill, There is a chance that

"Bill, There is a chance that you have a blown head gasket which is pressurizing the cooling system and blowing coolant out the overflow bottle, but that's just a hunch.

If you have the ability, do a compression check, this will answer this question."
 
"I HAVE A 5.7 ALPHA LX (25

"I HAVE A 5.7 ALPHA LX (250 HP) w/ about 300 hrs. on it. Seems to be running fine But last time out at full throttle, and ~4,000 RPM's she was only slugging along at ~ 28 mph instead of near 60 mph !!! I thought I blew the prop' bushing, etc... took out of the water, re-assembled it, etc... it appears to be properly engaged & fine... ? What's giving me my power loss, (bottom was pretty "fouled", but that shouldn't knock off half the thrust ! Right ???"
 
"<[img]"http://www.marineengin

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"Here is a pic of the exhaust

"Here is a pic of the exhaust down pipe is there supposed to be a flapper there or does this look right I haven't looked it up yet..
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"Boy, #8's not looking to

"Boy, #8's not looking to sporty either. Providing those cylinders are OK, I would pull the other head, get them reconditioned and tested, then reassemble it using new manifolds and risers. There is not much you can tell about the rings until you get the head back on but I'm bettin you will be fine."
 
"Yeah, there are supposed to b

"Yeah, there are supposed to be flappers on that pin. This could well be the root of your problem. This changes things a bit. You may not have bad manifolds but if they are over 4-5 years old, I would change them anyway. You don't want to do this again next year."
 
"is there a way to check the m

"is there a way to check the manifolds and risers or have them reworked in any way or once they go bad their bad.. also what makes them go bad, do they just get all clogged up or do they get worn out in some way.."
 
"The ports can get clogged wit

"The ports can get clogged with scale, the mating surfaces can deteriorate and start to leak between the coolant side and the exhaust side and in extreme cases, they can just plain rot through.

It is not a common tool, but I used to have block-off plates that I made to enable me to pressure test the manifolds. I also used to resurface the surfaces, but that was in the day when there was no real competition for quality replacement manifolds and the manufacturers could charge whatever they wanted for new ones. Now it's not really worth the time. Repairing them only buys you another year or two so you might as well go ahead and put new ones on."
 
"due to the cost issues that I

"due to the cost issues that I am having at the moment where is a place to get manifolds and risers for a good price, I have seen them on ebay but don't know about the quality.. what are your thoughts?"
 
well found out today that I ne

well found out today that I need new heads. also how do I find out if I have 3in or 4in manifolds.
 
"Bill:

I am not an engine

"Bill:

I am not an engine rebuilder. I was a purchasing agent by trade and dealt in monetary issues; best bang for the buck over a given time and what will serve the function I need for the least expense. I am a shadetree mechanic.

There are professional mechanics on this board that have the knowledge and experience necessary to help you make a decision.

Measure the diameter of the exhaust riser--the distance across the inside.

What year is the engine? How many hours are on it? How long do you plan on keeping it? What is the condition of the floor, stringers and transom? What is the current value of the boat w/engine fixed? How much for the heads? Should I have it rebuilt?

Those are questions you need to ask yourself to help you decide the course of action to follow. From the photos I saw, it looked like the one cylinder had some scoring or corrosion on the wall. That would concern me down the road if it was not addressed. Maybe I am wrong and it will be fine with a set of new heads.

head prices http://bpi.ebasicpower.com/c/ALL2A/Cylinder+Heads

1986 and below.............$200-300 each new
1986 and up................$329-339 each remand.
1998 and up Vortec.........$429 each new

Kind of makes that $1800 reman. engine and exh. mans. $429 set look good. I have not researched Jasper Marine engines out of Indiana but have heard many good and some bad about them. I used them to reman. diesel engines for a fleet of buses for my employer and it turned out not so good; problem was they were not highly experienced with the engines we sent them--warranties did cover repairs."
 
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