OMC guy needs help from the Merc experts!!!

[BoatingCop]

Well, I've always been an OMC guy and know those engines backwards and forwards, but the wildfires decided that they liked the engines more than I did. I'm now looking at an older boat with a 1975 Merc 150 hp. The guy says it has good compression, but it hasn't been run in two years. Now, if it was an OMC I wouldn't hesitate to jump on it because I know I could fix whatever is wrong. A Merc for me is a different story. On an engine of this vintage, what should I look out for, and what are common parts, besides a good carb cleaning and water pump, that need changing every so often? Is this a points ignition system or electronic. Learn me on the ways of the Merc so I don't sell it and stick a Johnson on the back of it!! just kidding. Are these older ones just as reliable if maintained properly? Thank you so much in advance!

 

[Mi duckdown]

Re: OMC guy needs help from the Merc experts!!!

Check the compression. I would not take any ones word on compression. whether OMC OR MERC.

 

[BoatingCop]

Re: OMC guy needs help from the Merc experts!!!

Absolutely...thats a given. I'd never buy anything wihout check it. Anything else? The reason I ask is because I know there are some OMC engines that you just want to stay away from. Anything like that with Merc?

 

[dwco5051]

Re: OMC guy needs help from the Merc experts!!!

These were great motors back then. They were electronic ignition with a belt drive distributor. As stated by others check compression. I would also while the plugs were out take a good look at what you can see inside the cylinders. Bad fuel flow leaning out the top one or two cylinders might show up if you take a good look. Look for burnt pistons or cylinder wall scoring. The biggest downside on these old Mercs is deteriorating or brittle engine wiring. The up side is nothing sounds as cool as one of these old towers running full out.

 

[BoatingCop]

Re: OMC guy needs help from the Merc experts!!!

Very awesome! I'm excited about working on something new. I've always loved the sound of the tower of power! Do the older ones like this have a tell-tale? The belt driven dist also sounds like it would be easier to time and do maintance on. Thanks for the help. Keep the suggestions coming!

 

[Mi duckdown]

Re: OMC guy needs help from the Merc experts!!!

Cop. If you want to work on this motor. Buy a OEM MERC Manuaul. Nothing else.

 

[BoatingCop]

Re: OMC guy needs help from the Merc experts!!!

Thats what I figured. Thats what I always bought for OMC. I hate the Chiltons manuals and others like it.