Survey for gas engines

H

Hap-E-Cruzer

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Going tomorrow to sea trial a Sundancer with 8.1 Merc Engines. Would like to know what to look for other than typical oil samples, compression, etc. How long should we ask to run these engines at WOT for temp checks? In a salt water application how long do the manifolds and risers usually last? It has closed cooling system, 250 hours, 8 years old. How do you know if they are starting to fail?
Anything else that would help?
Thanks...
 
If that engine is a full FWC system, meaning the manifolds are part of the closed system, there's no reason they shouldn't last the life of the engine. Risers on the other hand, if they are original, I'd say they are living on borrowed time.
 
I would have them pull any codes from the ECM's to see if there is anything lingering. Also a 1 hour seatrial would suffice, part of it at WOT.

MJK
 
quote:
Originally posted by king5899

I would have them pull any codes from the ECM's to see if there is anything lingering. Also a 1 hour seatrial would suffice, part of it at WOT.

MJK

Click to expand...


+1. Make sure the WOT test has the engines reaching Max RPM range recommended by Merc. If it does not or goes more than a couple of hundred RPM over, you have prop issues which will require a haul and prop work and possibly some storage fees.
 
You can run my engines at WOT for ten minutes after you have bought it. Forget it.

I want to see if they can hit WOT, but not run there for any length of time. I would however run the engines at around 80% of WOT for an extended period of time (say ten minutes) followed by the boat running at typical cruise for another 15-20 min, which will establish whether the cooling systems can support a realistic cruise speed.

Salt water cast iron risers are good for 3-5 or 5-7 years depending upon your locations norm. If zincs have been changed in the heat exchanger, it should last a long life, but that doesn't mean that it may not need a thorough cleaning. The areas that see salt water can also see marine life growth and concretions that over time may plug up the holes in the heat exchanger. If the boat passes the sea trial, it means it is functioning, but you should still have someone pull the heat exchanger end caps and inspect/clean after you buy it. "zeroing out" this component will get you another 5 years +/- before the next time. Just after boat purchase is also a VERY good time to zero out the risers (which almost always have been neglected and living on borrowed time) along with an inspection and rebuild of the raw water pumps and attached hoses (those don't last forever). You should really plan on zeroing out all of these systems on any boat your purchase unless the seller can provide convincing evidence that it was otherwise performed in the last 6 months.
 
Ghost,I understand your feelin's on the 10 mins as a owner I won't run mine like that, but as a buyer I did and yes a couple of sellers said no way...and I didn't buy their boats.
 
I would walk from a seller who would forbid WOT for a duration long enough to reach max RPM, but I wouldn't want MY engines run for 10 minutes at WOT, so I would respect someone else with the same concern.
 
If the engine and cooling system are in good condition, then running at WOT is not going to hurt anything. I would not see any benefit of running it any longer than 5-10 minutes. On the other hand if the owner is unsure about the engine(s) and is unwilling to have the engine(s) tested, then the buyer should take that into consideration. I would think that would be enough reason for a buyer to back out of the selling contract.
 
I have surveyed many vessels with these engines. Live data from the ECM control units will tell all. Fluid samples are very informative as well. Running the engines at wot for 10 min. or more is excessive! When a vessel is run under load conditions,the purpose is to insure the vessel will meet factory performance specs. I use thermal imaging to test the risers for restrictions or for any other over heating conditions that maybe present. It has been my experience that these engines fair very well.
 
Thanks guys, for all the input.
We surveyed and sea trialed last Wednesday and engines ran great. Surveyor ran at WOT for about 2-3 minutes and about 80% power for about 10-12 minutes and two different times.
I have advised my friend (the buyer) to have the risers and manifolds checked. No history of replacement yet. Prop seals were leaking, bottom needs paint, props our of spec. etc. Oil samples came back good. My biggest concern is boat has not been used (or licensed) in two years.
Surveyor did an exceptional job IMO.
Owner and buyer are still negotiating ......Thanks
 
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