496 HO Inspection points
04-13-2008, 01:37 PM
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496 HO Inspection points
Let's say someone was to buy a 2002 boat w a pair of 496 HO's w/ Bravo 1's w/250-300 hours on them. They sound good and have good maintenance records. But what would you have checked out?
Compression test?
Leak down test?I heard it takes a long time.
What Oil Pressure when @ temp?
Anything to look at in the drive?
What are some of the common problems at this kind of run time?
Thanks in Advance
Shawn
Compression test?
Leak down test?I heard it takes a long time.
What Oil Pressure when @ temp?
Anything to look at in the drive?
What are some of the common problems at this kind of run time?
Thanks in Advance
Shawn
04-13-2008, 06:10 PM
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250-300 hours means they probably never had a serious problem, but having said that you still should;
1. do a compression test- 150-160lbs
2. do a leak down test- 7-10%
3. Look at the spark plugs each cylinder
4. Use a scanner or laptop with software and download the history files and "guardian events" - overheats ,low water pressure, low oil pressure- Hrs at idle, hours at 1500 to 2500 rpms, hours at 2600 rpms to 4000 rpms, hours at 4000-5000rpms. How many times on the rev-limiters (over speed)
5. Take off the oil filter and have someone with the proper cutter, cut it open and look and see what kind of metals and debris inside.
6. When dry of water, look up into exhaust tips and look for a dry pipe, not one with oiled residue.
7. You could do an oil analysis , but without base numbers it would be a bit off but would show larger problems with high metals and such.
Chances are if the motors were well maintained and physically the boat, engine, engine bay and drive look like they were well cared for you should be in good shape if some fo the critical tests above do not show problems.
Being a solid , strong , reliable fresh water cooled engine that is easily capable of 750 - 1000 hrs with good service and use, you should be good for many years depending on your uses, service and care.
Remeber though, It's still cheaper in the long run to hire a good engine surveyor for twin engines and get some good testing than it is to find a major problem after sale and the associated hassles. Your making a big investment here ! "When in doubt, Check it OUT !!"
Good Luck,
Best Regards,
Ray @ Raylar
1. do a compression test- 150-160lbs
2. do a leak down test- 7-10%
3. Look at the spark plugs each cylinder
4. Use a scanner or laptop with software and download the history files and "guardian events" - overheats ,low water pressure, low oil pressure- Hrs at idle, hours at 1500 to 2500 rpms, hours at 2600 rpms to 4000 rpms, hours at 4000-5000rpms. How many times on the rev-limiters (over speed)
5. Take off the oil filter and have someone with the proper cutter, cut it open and look and see what kind of metals and debris inside.
6. When dry of water, look up into exhaust tips and look for a dry pipe, not one with oiled residue.
7. You could do an oil analysis , but without base numbers it would be a bit off but would show larger problems with high metals and such.
Chances are if the motors were well maintained and physically the boat, engine, engine bay and drive look like they were well cared for you should be in good shape if some fo the critical tests above do not show problems.
Being a solid , strong , reliable fresh water cooled engine that is easily capable of 750 - 1000 hrs with good service and use, you should be good for many years depending on your uses, service and care.
Remeber though, It's still cheaper in the long run to hire a good engine surveyor for twin engines and get some good testing than it is to find a major problem after sale and the associated hassles. Your making a big investment here ! "When in doubt, Check it OUT !!"
Good Luck,
Best Regards,
Ray @ Raylar
04-14-2008, 10:40 AM
#3
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I agree with Ray about everything except the leak down. If the cranking compression is normal, I don't see a reason to do a leak down. As far as the oil analysis, I would do it, but I have sampled many 496/8.1's so I have a good idea how they should look.
Just fyi, in '02 they were still using aluminum exhaust manifolds, which had bad corrison problems when used in salt water. If it still has the original aluminum manifolds, you may need to replace them.
Dave
Just fyi, in '02 they were still using aluminum exhaust manifolds, which had bad corrison problems when used in salt water. If it still has the original aluminum manifolds, you may need to replace them.
Dave
