Well we took it out the other night and the motor acted like it was missing and kind of revving up a bit. We changed the spark plugs and then took it back out. We think that actually sounds better now but while my husband was at the back watching the motor he noticed that no water was coming out of the holes. We have ordered a new impeller.

Any marine dealer can get you those parts. Check the wear plate and cup for any grooves near the driveshaft, if so replace the parts, if not just the impeller. You may not have water coming out of the exhaust relief. Your best bet would be to take it to a good service shop and have them go over the motor, install a tell tale or water pressure gage. Have them do a complete check of the motor. Since you guys are new to boating and the motor is almost 40 years old it is best to have an expert tell you what you have. While some things are possible for a DIYer with some good tools, many things aren't.

I have a 1990 Bay liner Cobra with a 1986 115 Mariner inline 6. I have had the boat for about a month now, and have honestly not had a day where I didn't have a problem. So far I have had the carbs rebuilt, the fuel filter pump rebuilt, the impeller replaced took it out ran fine for about an hour then stalled out and had to get towed back in.

Took it home called around and was told that my problem was the power pack because 1,3,5 was firing but others wasn't and when I swapped the two power packs the 2,4,6 started working. Well I bought a used one at the boat yard and got the spark back. Took it on the lake today and ran GREAT for about a quarter of a mile.

Then started cutting out and made the motor started jerking and wouldn't go over like 3000 RPMs (sometimes speeding up like it wanted to take off but would then start restricting itself again), but would run fine if I kept it under 2000 or 1500 RPMs shuddering at times. Made it back to the dock where we pulled the caps to the plugs off one at a time checking for spark. The plugs would spark fine fewer than 2000 RPMs, but would start missing on all of them if we got it over 2000. I have spent more time fixing this stupid thing than I have actually using it.

That motor is one of the best ever made. Essentially it is the same as the 150 of 1978 with updated ignition. First of all I would never recommend buying used ignition parts, you don't know how long they will last, have no warranty and may be on their last legs. Most of the switchbox's have updated components. I only recommend either Mercury's or CDI. As for your problem it would appear you have a bad stator. Mercury has put out numerous service bulletins on it. What is happening is you have two sets of charge coils and one set of alternator coils on your stator.

The stator is the series of coils under your flywheel. One set is the low speed, and the other the high speed. In your case the high speed coils have gone out. You will need to replace the entire stator. Here again I recommend you find a stator by CDI Electronics, have your local shop order you one. They have beefed up the coils and added another regulator. You will need special tools to remove the flywheel. Don't try to play with a normal wheel or pulley puller, you will damage the flywheel and will just have to go out and buy another one.

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