Engine Inspections

[mr_grumble2003]

Hey guys,

I’ve little outboard experience although not completely void of mechanical know-how and would like to get some tips on what inspections to carry out on that of a second hand 15-30HP outboard.

Obviously an inspection on a running engine is much much better, but if that’s not at all possible what areas should I be looking at ?

Initially thought of having an inspection carried out but if I am to view numerous engines it will obviously become an expensive exercise, and I wouldn’t mind knowing anyway.

Cheers.........

[BROWNIE]

I cant offer much advice mechanically, but I can recomend you test in the water. I looked at a motor earlier this year, it looked imaculate, ran perfectly on muffs. I put it in the water, idled out of the channel lovely then I gave it some stick, after 2 mins over temp alarm started. Outcome was a new head and thermostat total just under $1000. I was lucky enough to find this out before purchase.

So if you can check any motor under load.

[mr_grumble2003]

I cant offer much advice mechanically, but I can recomend you test in the water. I looked at a motor earlier this year, it looked imaculate, ran perfectly on muffs. I put it in the water, idled out of the channel lovely then I gave it some stick, after 2 mins over temp alarm started. Outcome was a new head and thermostat total just under $1000. I was lucky enough to find this out before purchase.

So if you can check any motor under load.

Cheers for that, some good advice there. Hopefully I'll tap into some of the other expertise within this forum as well.

[Grantm]

Looks can be very decieving with motors. Just cause it looks good doesnt mean it is, although it is a good place to start.

Like Brownie said you cant beat a water test to really know what its like, but you need to at least get it to run on ears or in a drum.

Look for obvious signs of damage and also signs that the motors has been stripped down by checking the bolt heads for signs of removal. Look for bubbling paint around the head which may indicate overheating etc. Look for signs of excessive corrision around gaskets etc. Pull the plugs out maybe and see what they are like. Just use commen sense and if it doesnt look right then leave it.

Buying second hand motors is a gamble so there is no guarentee your getting a goodin but when you do get one i suggest a good service including a new water pump to be on the safe side.

[Guest fishrunner]

I bought my 40hp 3 cyl yammy 2nd hand,

I did my standard checks

-taking a sml glass and undid the bottom oil screw on the gearcase and drain 50 ml out to check for water in the oil,- sign of new seals req'd.

-looking round for water on the ground and is the motor warm ,-alot of motors start 1st time once warm but what about on a cold morning, prefer to observe a cold start.

-spark plugs for carbon deposits, good telltale and idles smoothly, water test if avail.

-I also prefer if no water test avail then put it in a drum rather then earmuffs as I have seen a motor that had a nice telltail of water with muffs( more pressure) Put it in a drum and the impellor didn't pump water only dribbled under its own steam.

After all this went for a spin and afterwards checked gearbox for water again,- got a full cup of water before any oil came out(sneaky bugger had fresh oil in box) . Upon taking off leg then impellor housing to change impellor discovered previous owner had done backyard impellor change and stripped 2 of the screws that secure the housing(had to drill them out and re-tap - not bloody easy. Also replaced prop shaft seals, did a full service after what had been discovered. So I got stung a bit,- but the head and rest of motor were excellent with high compression.

As Grantm said service and impellor a must asap

This motor looked great and passed my humble tests, what was happening inside cost a few weekends and frustration.

Goes great now, doesn't use oil and am happy , but what an adventure it was

cheers good luck

Edited March 8, 2006 by fishrunner

[martinc]

Gearcase oil should be black - not white or milky - and not clear - just changed for some reason.

Rule of thumb - dont buy a scond hand motor over 10 years old. - about the life of most occasionally used motors.

Buying one a few years old, like my one year old Yammy 50, be weary of the motive. The one year old motor I bought, the seller wanted a bigger donk. He forgot to tell me the water pump housing was partly melted (possibly he did not know)- went fine on the flusher - but picked up when I immediately got it serviced to comply with the Yamaha 2 year warranty.

Check engine compression is equal between the cylinders. Check for corosion - you dont want the motor being the sacrifical anode for the boat.

You need a damm good motive to change a motor half way through its life on the back of a boat.