How many hours is too many on a motor

[RWilson2526]

I have a friend thinking of buying a used boat....trying to convince him to get a V-20 but I dont think he wants one....so he is not that good a friend.

Anyway....on ebay and Craigslist many advertisements state hours on the engine. how many is too many? I know the maintenance history is much more important than total hours but when someone says "only 300 hours" is that really only a little?

[Blue_Runner]

trying to convince him to get a V-20 but I dont think he wants one....so he is not that good a friend.

LOL!!

Wilson our resident motorheads would answer this a heck of a lot better than myself but I will say that in my opinion 300 hours isn't very much at all. As you said maintenance history and also how much it has sat, not to mention where it sat and where it was used.

I have a bunch of canned questions I always ask about motors like:
1) are you the orignal owner?
2) Has there ever been any problems?
3) When was the impeller last changed?
4) Salt water use?
5) What does your wife look like?
etc.

[spareparts]

I've ratehr have one with an average amount( approx 50-100 per season) than one with extremmly low hours(unless it was properlly stored). I've seen boats that were 5 years old an have 100 hours on them that were junk, and I've seen motors that had 4000 hours on them that ran like a dream. Hours isn't as important of an issue than maintance and condition.

[cterrebonne]

compression and leak down tell the real story. i have a guy that i sold a ficht to and he has over 1000 hours on it. i have also seens a new engine blow up at 5 hours.

[Steplift 72']

I've had well cared for engines worn out in 2 seasons of moderate usage and others run for 8 years without a blip. Hindsight is that overpropping a motor is an expensive mistake. Even a well worn motor will sometimes have fairly good compression, I've found that comparing WOT RPM will often show a couple hundred RPM loss before it's significant enough to show in a loss of cranking compression.

[Blue_Runner]

Hindsight is that overpropping a motor is an expensive mistake

Step, don't you mean under-propping? If not, what is it about over-propping? I've heard underpropping causes the motor to work harder, which makes perfect sense to me but I don't think I've heard of over-propping??

[Blue_Runner]

Ok I googled it...I think I understand now that if you are over propped the engine won't produce full RPM's, meaning you are working the motor harder. Maybe I'm just confusing myself here...heck I don't know what the hell I'm talking about! Somebody take me fishing!

[Seacrets]

Have a friend that recently got rid of a 150 hp Yamaha. It had 4600+ hrs on it. Original power head.

[cterrebonne]

comp check is a quick easy way to tell if she is gone or not, then if it checks out you run her and then get a leak down. theres really no way to tell if the bearings are good unless you tear the engine down, theres a hole in the side the block, or there is play in the wrist pin bearings.

[Steplift 72']

Originally Posted by Blue_Runner

Step, don't you mean under-propping? If not, what is it about over-propping? I've heard underpropping causes the motor to work harder, which makes perfect sense to me but I don't think I've heard of over-propping??

By overpropping, I mean too much pitch. Back in the late 70's I had a dealer sell me a 115 with a 19" prop. It managed to make just over 5000 rpm at WOT with a light load. The recommended range was 5000 to 5500 rpm. Loaded it ran 5000 rpm and accelerated slowly. By 250 hours it barely made 4900 rpm and had lost a few pounds of cranking compression on #1 cylinder. Later, a local dealer told me that he'd rather see an outboard slightly over the maximum end of the rpm range. His point of view was that he'd repaired many more motors being lugged than over revved.

My 1986 248 Offshore was propped to turn 6000 rpm with a full load and I sold it running well with over 2000 hours.