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Missing exhaust bolts is this possible

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nasdaqsam

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I just picked up a 2007 Pontoon with a 496HO with the Quick silver factory installed silent choice exhaust and only has 42 hours on it. I have had it for all of an hours worth of use. Ran perfect for the first couple of short outings. Then on the third I started to hear a noise coming from the engine. It turned out to be an exhaust leak. Well upon further checking there were 6 of the 8 bolts missing from the port side exhaust. The remaining 2 were hand tight. This boat has a sealed bilge so if they fell out they would have been in the bilge. We used a magnet and fished around the bilge, no bolts to be found. We did find a few misc. boat build type screws etc but no exhaust bolts. I checked with the former owner he claims he has never touched the engine. He did a little work to the Bravo 1 X in plugging the cone water inlets and put on a brass water pump. But never touched the engine. He has been pretty straight with me about everything to do with the boat so no reason to not believe him. Again it has only 42 hours. I looked around the engine for signs the that it could have been worked on and there are no marks or paint off any bolts etc. Is it possible the engine was missing the bolts right from the start? The new bolts went right in so none were broken off. Could that side of the engine have just been missed? It just doesn't seem possible for this to happen or for the engine to run for 42 hours with no issue then all of a sudden I get an exhaust leak.

Opinions?
 
I bought a factory fresh MERC 5.7MIE. Would not idle quite right. Took carb off and discovered that the spacer underneath the carb was installed upside down, i.e., the "This side up" marked side was down. This resulted in a step/offset in the bore under the carb as the spacer is not symmetrical. Paint on carb bolts was undisturbed before I removed them. Mechanic told me I had a "Friday quitting time engine".

In your case, it's possible the two bolts were tight enough (before multiple run/hot, cool cycles) to keep the joint sealed for awhile. In time, bolts worked themselves looser and bingo! Tightening specs for bolts are for a torque that will intentionally stretch the bolts very slightly ( or compress the lock washers) so that heat/cool cycles (and vibration) will not allow the bolts to loosen.
Often in a hand assembly operation, two bolts are initially installed so as to hang the two pieces and their gasket together in alignment and later ( usually almost immediately) the rest of the bolts are installed. You could complain to MERC. In my case they offered to pay for a mechanic to fix it, however I had already done that. Check warranty time on engine.
 
Last edited:
sandkicker said:
I bought a factory fresh MERC 5.7MIE. Would not idle quite right. Took carb off and discovered that the spacer underneath the carb was installed upside down, i.e., the "This side up" marked side was down. This resulted in a step/offset in the bore under the carb as the spacer is not symmetrical. Paint on carb bolts was undisturbed before I removed them. Mechanic told me I had a "Friday quitting time engine".

In your case, it's possible the two bolts were tight enough (before multiple run/hot, cool cycles) to keep the joint sealed for awhile. In time, bolts worked themselves looser and bingo! Tightening specs for bolts are for a torque that will intentionally stretch the bolts very slightly ( or compress the lock washers) so that heat/cool cycles (and vibration) will not allow the bolts to loosen.
Often in a hand assembly operation, two bolts are initially installed so as to hang the two pieces and their gasket together in alignment and later ( usually almost immediately) the rest of the bolts are installed. You could complain to MERC. In my case they offered to pay for a mechanic to fix it, however I had already done that. Check warranty time on engine.
Click to expand...
So it is possible. Man thats a big miss step in a motor of this HP. Thanks for the reply.
 
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