OMC guys! Engine Lifespan?

How many hours can I expect to get out of my 1975 OMC 175 I/O? It has just over 300 hours now. Only 2 owners since new, and they confirm hour meter is original and correct hours. Other than regular maint. (plugs, points, oil etc.) any major component replacement/rebuilds to expect at XXX hours?

I know it's old, so will be running it accordingly. I won't be hot-rodding or running WOT alot, just a little skiing/tubing with the kids. And I have a kicker for trolling so not alot of low RPM hours either. Will mainly be running A-B at a nice cruise of 35mph (WOT 42mph. sorry tach not working right yet so no rpm's)

Thanks in advance for any info!

Colin

Re: OMC guys! Engine Lifespan?

How many hours can I expect to get out of my 1975 OMC 175 I/O?

What engine did OMC use for the 170hp,..???......

Most Engines will Easily run 1000hrs......

Most Engines Could run 2000hrs if they were taken care of.........

Most Die from Neglect,.... Or being Frozen.........

Re: OMC guys! Engine Lifespan?

Thanks for the reply Bond-o. The 170/175 hp's are a ford 302 engine. New on the engine are:
-coil
-cap&rotor
-points/cond
-plugs/wires
-ballast resistor
-oil&filter
-fuel filter
-carb rebuild
-starter soleniod
-trim solenoid
-leg tilt motor
-tilt clutch pack
-thermostat
-all rubber hoses & belt

Right now, everything seems to be running within specs. Idles nice @ 550-600 rpm. Temp @ cruise 160-170, oil press @ cruise 45-50psi, alternator charging at 13+volts. Only thing not reading right is tach at higher RPM's. (see thread in electronics forum!) So far I'm a happy guy! Just wondering how long it will last!8)

Re: OMC guys! Engine Lifespan?

NW said:

Just wondering how long it will last!8)

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Keep the oil clean, don't let it freeze, don't run it at WOT all day long, 2000 hours. I had 1500 on my '75 190 hp before a freeze got it. It ran like a top, still had normal power and didn't use oil.

Re: OMC guys! Engine Lifespan?

Thanks Boomyal! Is that for engine AND outdrive? Anything in the outdrive gonna give up before the engine? (Besides the ballgears if the leg's not fully down!)

Re: OMC guys! Engine Lifespan?

The drive life is very subjective. There again maintenance and non-abuse is the key.

Re: OMC guys! Engine Lifespan?

Thanks KaGee. Anything in particular to watch for on these old OMC's? Is there a recomended # of hours to replace impeller etc? Nothing mentioned in my manual, just how to replace if needed.

Re: OMC guys! Engine Lifespan?

NW said:

Thanks KaGee. Anything in particular to watch for on these old OMC's? Is there a recomended # of hours to replace impeller etc? Nothing mentioned in my manual, just how to replace if needed.

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I think you are aware of the main issue already... don't start the motor with drive tilted up. A tilt of 15-20* is acceptable for emergenies in shallow water... but get it back down ASAP.

Keep your shifting RPMs to 650-700 max. If your carburator does not have a throttle return spring (OMC did not use one) add one on.

Keep the tilt pivots greased.

The impeller will last several seasons (depending how much it's used) provided you do not turn the engine over without being in the water or with muffs on. There is a "pee hole" on the intermediate housing where a stream of water shoots out to cool the ball gears. As long as there is good steady stream there, you know the impeller is working.

Re: OMC guys! Engine Lifespan?

Be gentle with the shifting of the electric shift OMC. This is especially true when running a stainless prop. Make sure you don't switch from forward to reverse( and reverse to forward) too fast. You want the prop stopped between shifts.

Make sure you use the type "C" lube in the drive.

Check your drive lube often for water. Those drives had a tough time keeping sealed.

Re: OMC guys! Engine Lifespan?

Just an opinion but if longevity is the goal for an older drive stay away from Stainless Props. They are heavier which may contribute to wear and they transfer more shock if you hit submerged objects which may damage internal parts. Ditto on everything else and three absolute things; maintenance, maintenance and maintenance.

Re: OMC guys! Engine Lifespan?

Thanks for all the tips guys. Glad to know I've got a few things right along the way! I've got the little 'owners manual' and a Glenn's 'shop manual' and have stuck to them as closely as I could with specs/lubes etc.

My idle is right at 575-600 rpm as set with tach/dwell meter and I'm alot more careful shifting than I was with the work boats when I was fish farming! :devil:

Throttle return spring? Tell me more o wise one! How 'stiff' of a spring do I need and where to mount it? Is it just to make up for any 'slack' in the linkages and make sure the throttle comes right back to the stop?

I've got good water flow out the 'pee hole', and never start it dry. I flushed it for a good 20min before the first time I ever tried to fire it. After sitting so long I didn't know what to expect when I turned on the water! lol She runs a steady 160-170*F @ wot so I think I'm OK for now, I just wasn't sure how much life it had left in it. Just over 300 original hours on the whole drive package right now.

The oil still looks good with about 8 hours on it so far. (since the resurection!o ) I think I'm gonna change it (motor and drive) at about 15 hours just because. I'd love to pull the oil pan for a look-see but let's not even go there!

I'm gonna stick with aluminum props too, just to reduce the chance of damage in case of impact. (to my wallet!)

Re: OMC guys! Engine Lifespan?

I agree with Purduebarry that aluminum is more forgiving.

My family used to boat up in the Canadian inland passage where you are for years with your exact same stern drive. We had so many dinged aluminum props from hitting driftwood that we switched to a stainless prop. We never had a problem with a damged prop again.

That was then when the drive was fairly new and parts were plentiful...now might be a different story.