How many hours is too many on a motor
 

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?

LOL!! :nut:

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.

:zip:

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.

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.

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.

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??

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! :beer:

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

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.

if you are asking for a rule of thumb, i have always heard on average and outboard lifespan is approximately 1000 hrs, with the average recreational boater using it 100 hrs a season. all of the above are correct though, commercial guys get thousands and thousands of hours and trailer queens much less. like all rule of thumbs, there are many exceptions to this one.

side note: we were chainsaw dealers from 69 to 86 and then the average life of a homeowner chainsaw was 4 to 6 hours.

Ha ha I believe that.... sounds like me and lawnmowers:fight:

talk about propping heres my motor after about 25 hrs of running the wrong prop.... I repeatedly told the A- hole who sold me the motor that I didnt think it was propped properly ( say that 3 times fast) and he kept saying thats the prop brp recomends...... needless to say he was wrong .....blown powerhead on a brand new motor.....:fight: thank god for the warranty.... zero out of pocket expence , only two weeks lose of time ......

http://i115.photobucket.com/albums/n...8/DSC04187.jpg

lumber what was your max rpm's?

5600 to 5800

and was only running at the time 4700.

you were only turning 4700 wot? wow, you bought that engine from a dealer?

yes I did , hes was so busy i became just a number to him, once he got my money he was done with me.....

man that sucks bad, sorry to hear. they have a dealer about 1.5 hrs away that does that same thing. I dont think they have a real rigging dept.

I was told,...and believed'm that my '77 I/O had around 3000 hours on it. It ran fine and was only replaced due to a screw getting sucked down the carb and landing on a piston which blew a hole in the head. Otherwise it'd have about 4000 hours by now.

re;OBs,...I had a 20 year ld "115 "rude that ran strong till it caught fire and burned up,...while still running all the way across biscayne bay.

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.

motors being damaged from lugging is even more important now than ever with the newer four strokes on the market.