Mercrusier 120 problems with starting

[Mschramm10]

Nice weather is finally here in NY and looking to get out on the lake. Charged the battery up and found that the engine won't turn over. Ok 5 minute conversation with my local boat mechanic and found a bad starter solenoid. Got that changed out and now it's turning over like a champ but won't start. Plugs are sparking good and new ignition items as of summer of 2014 (doesn't mean it's not bad) I only ran the boat last year twice due to the fact of needing a complete bellows replacement so we got a late start. Any ideas as to why it's not starting?

 

[bobkat1864]

Hi there, well if you have spark, you need air and fuel to make her start. Air is pretty much a given, so the next logical step would be to check your fuel delivery...make sure you don't have old gas with water in it, and that the engine is actually being fed. As long as there is spark, air and fuel, she should at least try to start. Let us know what ya find, and good luck.

 

[Mschramm10]

Thanks bob! I meant to be a little more clear than I was. I checked the spark plugs outside of the boat and they were good but wasn't sure of the process of check them on the boat(checking to see if distributor is working?) the reason I say this is the solenoid went bad, I'm sure, because it got wet and corroded and wasn't sure if the same thing happened to the distributor? I want to make sure I have spark before I dive into the carb. ( sorry for the misunderstanding with the spark plugs)

 

[bobkat1864]

Ah ok, not a problem at all...the best way I know to check for spark in the boat is to use a spark tester...they can be had for cheap or maybe borrowed from a parts store. I even recall reading a thread on here explaining how to make one...if you use the search feature and type in "spark tester" there is a lot of info that you may find handy. Let us know what ya find.

 

[Mschramm10]

Did a little more research today with my volt tester and found that I have no voltage whatsoever going to any of the plug wires. I have between 9-12 volts at the blue "canister" located just above the distributor cap. (Excuse my lack of terms I am still learning!) I opened the cap and everything looks new and un-corroded. Any ideas on what to check from here? Points? Condenser?

 

[bobkat1864]

Ok, the blue canister is your ignition coil. It will have a small + and small - terminal and a big wire coming out of the top that goes to the distributor. Check to be sure there are 12 volts on the small + terminal when the engine is cranking. This power comes from the starter solenoid and once the engine starts, the power comes thru the run side of the ignition switch. You have the power from the run side, so let's be sure you have it while cranking. If it is there, try cleaning your points with some fine sandpaper. Report back what ya find.

 

[Mschramm10]

All was well with the voltages to the coil so I cleaned the points and it fired up in a few tries. Next problem...it ran beautiful for just about 10 minutes and rev'd up slightly and died and wouldn't start again. I was sure it was points so I will be grabbing a new set of those tomorrow as nothing is open on Sunday!

 

[Mschramm10]

I also decided to check the oil since this is the first time the engine has run since I did an oil change. I found that the oil level was just under the "add 1 quart" mark so I added the one quart. I came back 15 minutes later and rechecked, oil level was good but found a milky color in the oil. Please don't tell me I'm running into a new issue!

 

[savetexomabeaches]

milky oil is water in oil and that can be a big issue

 

[bobkat1864]

Ok, got her to fire up, so we are on the right track...new points and condenser is a good idea, since you know they are suspect anyways. Recommend cleaning the mounting surface really well too, when you install them. Milky oil...well if water is getting into the oil it will foam up and look like a milkshake, and the oil level will rise. Keep a close eye on it, and time will tell. Let us know how ya make out.

 

[Silvertip]

Keeping an eye on the oil level means every few minutes until you are sure foaming and a rise in oil level isn't occurring. Oil pressure and water temperature monitoring is also required. Water in the oil is not a good thing and will destroy an engine.