500hp Engine Hours?
03-17-2005, 03:46 PM
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500hp Engine Hours?
I'm looking at a boat with Merc 500hp's. The thing does not have an hour meter anywhere. I looked in the engine compartment, under the dash, under rear seat, everywhere. The boat is super clean and the owner thinks it has close to 200 hrs. It is a 97. Is there anyway to find the hours of this boat. ignition, tachs? I am going to have a complete leakdown test done but I know that these engines need valve springs replaced around 300 hrs. I really like the boat but I hate the idea of not knowing at least an approximate hours of operation. Thanks
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03-17-2005, 04:03 PM
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Re: 500hp Engine Hours?
They must be Carb motors , in 1997, NO, there is no way too know how many hours are are them. If 1997 got to be more then 200 maybe 400 if used all summers. I replaced my valve springs and would also do the lifters. Have heard of some going 500 hours before rebuild but not me.
03-17-2005, 04:20 PM
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Re: 500hp Engine Hours?
Originally Posted by excursion
They must be Carb motors , in 1997, NO, there is no way too know how many hours are are them. If 1997 got to be more then 200 maybe 400 if used all summers. I replaced my valve springs and would also do the lifters. Have heard of some going 500 hours before rebuild but not me.
03-17-2005, 05:06 PM
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Re: 500hp Engine Hours?
Originally Posted by Perfectmix
Oops! Forgot to mention they are carbed. I know the owner did not use the boat hardly at all. It sat in his barn most of the time. Also I know it was not abused. I would seriously look at freshening the entire engine upon changing valve springs.
03-17-2005, 05:55 PM
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Re: 500hp Engine Hours?
A friend of mine had a pair of 99'
carbed 500's, that had vavle spring
issues under warranty.
MerCruiser requested the Ignition modules
to be sent in, so they could read how many
hours they had a each thousand RPM
increment.
The weird thing about it was that
you would think that the hours above
the 2000 rpm level would be near identical,
being that if your going to be running on
one engine, I doubt you'd be running on
one above 2000 rpm.
As I recall, they were off several hours
throughout each RPM range.
The total hours also didn't equal what the hour
meters read, also.
None the less, it gives you an idea of approximate
hours.
His ignition was thunderbolt V, my 98' has
TBV, I don't know if 97's had TBV, or TBIV.
I Know my friends 96' has TBIV.
I don't know if this data can be retrieved from
TBIV modules, if that's what they end up being
equipt with.
carbed 500's, that had vavle spring
issues under warranty.
MerCruiser requested the Ignition modules
to be sent in, so they could read how many
hours they had a each thousand RPM
increment.
The weird thing about it was that
you would think that the hours above
the 2000 rpm level would be near identical,
being that if your going to be running on
one engine, I doubt you'd be running on
one above 2000 rpm.
As I recall, they were off several hours
throughout each RPM range.
The total hours also didn't equal what the hour
meters read, also.
None the less, it gives you an idea of approximate
hours.
His ignition was thunderbolt V, my 98' has
TBV, I don't know if 97's had TBV, or TBIV.
I Know my friends 96' has TBIV.
I don't know if this data can be retrieved from
TBIV modules, if that's what they end up being
equipt with.
03-17-2005, 10:13 PM
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Re: 500hp Engine Hours?
Oh yea, Comp cams 929's are the springs you need to use. It is also cheap insurance to upgrade the locks and retainers while you are in there. You can change em in the boat as long as you have compressed air to keep the valves up.
