Merc 78A engine starting trouble

TreelineIII · Post by **TreelineIII** » Mon Oct 15, 2007 7:14 am

Hello, and help. Well I am at that stage where I thought I should see if the engine would work. It has not run in about 5 years. The previous owner apparently would start it every year, but not for very long and only in a bucket. When we tried all we got was barrely a click out of the starter. To start with we are charging the battery thinking this may be a contributing factor. The other is that the prop is very hard to turn. Should the prop spin with ease? Keep in mind, this motor is a 1958 direct drive engine and has no neutral. Rather then electric start I attempted to use the pull start of which was very difficult to pull. To the point I could not acctually pull it our very far, and certainly not fast enough to start a motor. Any help, insight is welcome. Anybody in the Chicago area want to have a look see I would be pleased to pull the boat by an let you take a look. Thanks for any and all comments.

a j r · Post by **a j r** » Mon Oct 15, 2007 8:30 am

The impellor for the water pump in the lower should be replaced before attempting to run the motor. That's step number one.

I am not a motor head, so cannot reply with any confidence.

I suggest posting your questions at www.aomci.org in the "Ask A Member" discussion forum area. They have very helpful people and there are chapters all over North America. There probably is one in Chicagoland. Get to know some of those folks and find the Merc gurus.

Andreas

thegammas · Post by **thegammas** » Mon Oct 15, 2007 3:53 pm

Could be a number of things making it hard to turn the motor, Stuck rings, stuck lower unit, even stuck pull start mechanism. Take out the plugs and spray a liberal amount of a penetrating oil in the cylinders and let sit for a day or two. Bonus points if you can have the motor sitting on the ground such that the cylinders face up and level to allow the penetrating oil to get all around the rings.

Lubricate the pull start mechanism. You should be able to reach it by removing the cowl. Replace the lube oil in the lower unit. When you drain it, look at the oil to see if there are any metal shavings and look for any milky coloration (which would indicate water is making into the lower unit, which can cause it to be....sticky.

Andreas is correct, before you run the motor, replace the impeller. You can kill a motor quick by running it just a few minutes with out water. Worse, the impeller could break up and the bits move up the water jackets and clog them.

You can get tons of advice at fiberglassics.com/outpost, which is an Old Mercs forum. You can get most all the parts you need for repairs and tuneups at oldmercs.com

JoeCB · Post by **JoeCB** » Mon Oct 15, 2007 6:21 pm

ditto all of the above suggestions/ comments. Also a motor that has been sitting for 5 years most likley will need to have the carburetors cleaned of old gunky gas residue. and ... the breaker points in the magneto are likley oxidized and need to be cleaned before you will get any spark. I too strongly suggest that you hook up with the local Antique Outboard Club chapter, you wil find the guys most helpful
Joe B

TreelineIII · Post by **TreelineIII** » Wed Oct 17, 2007 6:07 am

Problem Solved....................or at least resolved.
As many of you know from reading my various emails I am not an engine guy. As much as I am sure this motor has a continued future life, it will not be with me. Since my plans are fo an enjoyable family boating experience, I have opted out on this engine and as of yesterday I bought a 1976 merc 115. Looks good, sounds good, and off to the next project I go. I know many of you are motor guys and might just enjoy this engine. If any of you are interested let me know. I have never spent alot of time trying to figure out how to post pics here, sorry. If you are interested you can send me an email at Eric_Platou@malloy.com and I can try to send a pic, or at least talk with you about it. Thanks again for all of your help.
Eric