Mercury 115 4 Stroke EFI engine life.

[ezcartdude]

Any one have a idea or know how many hours a properly mantained 4 Sroke engine should last with proper maintance? If I remember Greg F changed his out at around 3000 hours and it still was in good shape. Whats the highest number of hours anyone has ever seen or heard of? Would you be nervous about purchasing a 4 stoke that had 3500 hours on it that looked clean under the cowling and ran good? Thank for any information.

[GregF]

The biggest problem with old outboards is the stuff that is not really the "engine". Power tilt/trim and lower unit problems can get real expensive real fast. Then there are the little screw on parts that can "hundred dollar" you to death, just for the part. A starter that might be $40 in a car, will be more like $400 on an outboard or even an inboard because it needs to be "marinized". (basically a dime's worth of screen over the holes that ends up costing hundreds of dollars).

Then there is corrosion, particularly in salt water.

[ronb]

3500 is getting sort of high, but the purchase would depend on some other factors too, get the engine hours print out from a mechanic to find out how the engine was used. They can tell you approximately how many hours the engine spent at different RPM ranges. If the hours at particular RPM ranges does not match the total hours that is because somewhere along the line somebody reset the computer to 'break in mode' and it started collecting statistics all over again. On my previous power head the total hours were 1050 but the statistics from the motor were only from the last 540hrs.

So back to those other factors...
1. How much are they selling it for?
2. Are they offering any sort of warranty?
3. Can you afford to replace the powerhead ($3500 for my 90hp Optimax from Mercury) or the drive (no quote as I didn't need one, but assume $1500-2500) or the computer ($1000 for a Mercury replacement for my 90hp Opti)
4. If your pontoon has a motor, how much is it going to cost you to convert (if it is a different manufacturer you will most likely need to swap out the shift/throttle)
5. Do you like/trust the sales person?

Having recently bought a used boat, I did poorly in my pre-sale evaluations and it bit me in the kiester very hard. Before you even start talking about cost/value with the seller have it checked out

Compression
Leak down
Oil Pressure
Fuel Pressure
maybe even have them do a bore scope (like endoscopy for your motor, stick a remote camera down the spark plug hole and look at the current condition of the cylinders, head, valves, pistons)
See if they have done any maintenance (filters, spark plugs $10/each my opti, coils $120-160 my opti)
Get the computer information about the engines life so far

I might also ask if they have replaced the prop recently, sort of a side ways question about how careful they were about running into things, my brother in law has replaced his 3 times in the last year due to breakage... not good.

When you see prices listed above that is because I either had to replace it already, or due to issues, there was a possibility that it was going to need to be replaced.. I have only had this pontoon/motor since 4/30... you don't want to buy a lemon... do your homework first..

-ron

[slingshot]

I've found that when checking out really old or high hour engines it comes down to three things: compression, compression, compression. In principle, compression is how all engines generate HP. If the compression is at factory levels or close and no two cylinders are more that 10% off from the other, and she idles and runs smooth your good to go. As Greg said, it's the other parts that you'll have to look out for. Drop the lower unit drain and fill plug (the bottom one) and see if the there is water contamination (white fluid) coming out. The plug is also magnetic so see if there is much metal on it. Engine and lower unit are the 2 big money holes. All that having been said. I would never value an OB more than $1500 with that many hours on it. If you buy it and it lasts you one season then count yourself a winner. Anything more and your a really big winner.

[LocoCoco]

On what boat and for what purpose did it clock 3500 hours?


If everything checked out ok, I'd consider it at the right price. And by "right price" I mean significantly less than comparables with 1/4 the hours.

ie. A couple years ago I saw an '01 Grand Cherokee with 505,000 km (314,000 mi.) priced at $4000 while typical Grands with under 200K were priced around $4500. Ya, the thing apparently ran great, but at that mileage its days are numbered no matter how well it was taken care of and a 10% lower price is a joke.


LC.

[Bamaman]

It'd have to be priced right with such high hours. I'd also want to inspect the boat the engine was mounted on--to see how well maintained the boat was by the owner.

One thing that's so overlooked on used motors is the lower unit. On any used boat, I'd want to personally drain the lower unit--looking for water. Then, I'd want to have a dealer pressure test the lower unit, to make sure that the seals are good. A seal kit and labor to replace them is between $250-300 on most lower units. It'll cost you about $845 plus freight for a new aftermarket lower unit on most popular motors.