115 inline 6 Merc

[ramboot]

Just took compression test on merc 115 hp starting top cylinder down all read 120 compression until i hit #5 ZERO COMPRESSION? And bottom was 120 also. Shouldn’t there be some kind of reading on the fifth one down? Does this mean I just got hosed by seller? Fix?

 

[jimmbo]

Did you repeat the test, just to make sure you didn't have a leak or the bleed valve on the gauge was stuck open?
If you did and got still got Zero, you have some serious problems with #5. Have you had the engine running?

 

[racerone]

Agreed.----What is the serial #

 

[Chris1956]

After repeat of compression test, it will be time to take off the lowest transfer port cover (starboard side) and inspect the rings, piston top and cylinder walls on cylinder 5.

 

[ramboot]

It’s just kind of weird that there would be no compression what so ever when all others are 120, the guy I bought it from said he had it out last fall on Columbia lake and ran good with no issues. Just looking at bill if sale looks like serial number is 718447? Not at home right now to check. Is it a big job do the one cylinder if needed?

 

[ramboot]

I forgot to mention I have not had it running and owner said he had it tuned for operating at a different sea level? Living in British Columbia

 

[racerone]

I say it is not impossible to do that job at home.----But it depends on your aptitude and skill level.-----Invest in a manual.-----Getting a shop to do that could well lead to a $3000 touch.

 

[Faztbullet]

Get your money back...….

 

[jimmbo]

Is it a big job do the one cylinder if needed?

Once you have it apart, you might find that the other 5 are less than great too. In any case, once its apart, you might as well deglaze the better cylinders and replace the rings. Parts for those motors are still available, but Mercury has jacked the price of Pistons into the Stratosphere(they want you to buy a new Torqueless 4 stroke, instead of repairing the old 2 Stroke)

 

[havoc_squad]

Once you have it apart, you might find that the other 5 are less than great too. In any case, once its apart, you might as well deglaze the better cylinders and replace the rings. Parts for those motors are still available, but Mercury has jacked the price of Pistons into the Stratosphere(they want you to buy a new Torqueless 4 stroke, instead of repairing the old 2 Stroke)

It doesn't help that consumer demand is channeled into a disposable product mentality for convenience and profit.

If the incentive to make things last isn't there, or the penalty for being excessively wasteful isn't there, old product support will be aggressively terminated and they will push new products intentionally engineered to fail after a certain period.

It doesn't cost a fortune for most situations to build a long lasting washer & dryer, or marine engine fuel & ignition system that doesn't ask miracles to be made for emissions. The problem is that's not profitable enough.

Now, in 10 years they probably want the critical parts to wear out and fail and cost too much to repair, forcing a new purchase. Washers & Dryers are an excellent example of this trend.

 

[ramboot]

Can I get a good online service and repair manual for this motor? Serial number is 7184417 for this motor. Thanks for the help

 

[Faztbullet]

Ram...Unless this motor is very sentimental to you or need it for a restore project forget about repairing it. You can get a later model motor for about what your going to spend on this. The only way that cylinder has no compression is : hole in top of jug, major cylinder damage or preignition has produced aluminum throw off and sealed spark plug hole. If this motor has a lot of hours you are going to find the cylinders worn around the transfer port areas and all will need rebored. You can spend a $1000 in parts only and finding someone to bore a blind hole is hard!!! If the jug or cylinder is damaged welding and resleeving can run up to $500. A replacement block(used) will likely need bored to so back to square one...and you have to figure out what caused the failure as if you don't it will happen again.

 

[havoc_squad]

Ram...Unless this motor is very sentimental to you or need it for a restore project forget about repairing it. You can get a later model motor for about what your going to spend on this. The only way that cylinder has no compression is : hole in top of jug, major cylinder damage or preignition has produced aluminum throw off and sealed spark plug hole. If this motor has a lot of hours you are going to find the cylinders worn around the transfer port areas and all will need rebored. You can spend a $1000 in parts only and finding someone to bore a blind hole is hard!!! If the jug or cylinder is damaged welding and resleeving can run up to $500. A replacement block(used) will likely need bored to so back to square one...and you have to figure out what caused the failure as if you don't it will happen again.

+1.

At least you might want to focus on later model used carb only two stroke outboard that have currently better parts support and documentation.

1979 to 1998 V4 OMC crossflow outboards.

1989 to 1997 Mercury Inline 4 100/115 hp outboards.

Others may have better recommendations, but I think these stand out as your best bang for your money when used and in good running condition.

 

[racerone]

But one of those 6 cylinder inline motors when rebuilt are just one sweet running / smooth / reliable motor.----So worth investigating.-----When you are done you will have a motor you understand and will not require $100 + / hr dealer support.

 

[Faztbullet]

I agree Racer but if customer is going to drop $1500 on one of these for repair I myself am going to suggest them find a new motor to that that on. As it stands his motor is only worth abut $300 in that condition in my area.

 

[racerone]

Sorry ---Fazt----I am well aware of shops doing the customer a favour by suggesting a new / newer motor.-----It is the owner of this motor that must decide on what to do.----I get much newer motors for less in my area.