HELP!!! Mercruiser 3.0 not starting

[matthew251]

Hello everyone! I am new to this and a new owner of a boat. I have an 84 Larson citation. And it apparently has a (new engine as of 09) put in it. It is a mercruiser 3.0 140 hp 181 CID.

Here's the deal. When I went down to purchase it, it started up great and ran for awhile awesome. The boat had about 1/4 of a tank in it when purchased. Girlfriends father put in another 8 gallons. We took it out the first day for about 7 hours and did pretty good. Had a slight hesitation when accelerating around 2000 rpm's. I just thought that was something that would go away. Then we ran it the next day and just the same thing. We could cruise at WOT great and just a slight hesitation when accelerating.

Then the boat sat for about 10 days with 1/4 tank in it. Then we went out and put about 13 gallons of 87 grade in it and one bottle of heet to pull out moisture. Didn't know if that was good or bad. Then that same day we took it out and still did the stall around 2000 rpm but was cruising for about 30 seconds at WOT and just completely cut out. Started up and got to WOT and cut out again. Got back to the dock stumped.

A couple days later noticed choke was stuck open. Fixed that problem. Didn't stall out that day. Next day it did.

Then it sat for another 4-5 days. Went down and now it won't even start at all. Then had someone come out to look at it and what do you know it started. He said timing could be off but only a couple degrees.

Replaced plugs, wires, distributor cap and rotor. Hasn't started since he came out which was yesterday.

I also noticed that it backfired through the carb when i was trying to start it.

Could this simply be bad fuel? Or is it electrical situation? I need help!!! We are having friends over for memorial day and plan on taking out the boat!!!

[fishrdan]

How are the fuel filters, been replaced yet? Try squirting a bit of fuel down the carb and see it it fires.

Have you tested for spark?

How about the points and condenser (if it's a points dizzy)

Dead-mans safety switch tripped or shift interrupt switch hung,,, killing the ignition.

Hesitation on acceleration sounds like a bad accelerator pump, time to rebuild the carb.

If you are worried about water in the fuel, install a water separating fuel filter.

[littlebookworm]

An 84 boat won't have an engine kill switch. The most likely cause is your carb. I suggest you pull it and have it rebuilt. Make sure it soaks in cleaner overnight and that all the inner passages are blown out cleanly. Do not add "Heet" to the fuel; buy a container of the proper Staybil or other brand fuel stabilizer. Add a fuel/water separator if ther's none there. Make sure all your fuel lines are ethanol rated. Hopefully, this should take care of your problems. I suggest you download manuals for the engine and outdrve. That way you can become familiar with the mechanicals of the boat. There are a few sites online where you can get manuals for free, including
4shared.com. Good luck. Hy

[matthew251]

The fuel filter near the carb had a little junk in it. We just cleaned it with fresh fuel. But I've read in my manual that there are supposed to be a spring along with a few washer in with it. Its actually all alone. Also the other filter didn't look bad. Maybe I'll replace those tomorrow.

I also bought a fuel water separator installed it on the boat just havn't had time to hook up the new fuel lines to and from it.

Sometimes when cranking over, the engine will start firing and as soon as I think it's actually running up to about 2000 rpms, I let of the key and it just dies. I will have someone come up and see if the coil is operating correctly tomorrow.

Sorry for my lack of knowledge but how do I check the points and the condenser? I have talked to someone about the problem and he said could be the points as well. But I have no clue how to go about that.

I am starting to get frustrated because it seems like it gets so close to starting, then doesn't. I don't understand how it ran the other day and started fine each time and then BAMMM. Crappy times lol...

[fishrdan]

The fuel filter near the carb had a little junk in it. We just cleaned it with fresh fuel. But I've read in my manual that there are supposed to be a spring along with a few washer in with it. Its actually all alone.

Sometimes when cranking over, the engine will start firing and as soon as I think it's actually running up to about 2000 rpms, I let of the key and it just dies. I will have someone come up and see if the coil is operating correctly tomorrow.

Sorry for my lack of knowledge but how do I check the points and the condenser? I have talked to someone about the problem and he said could be the points as well. But I have no clue how to go about that.

The fuel filter needs to have the return spring, so it seats against the seals, no return spring means junk can get past it. Junk that could be in the carb now.

If it runs while the key is turned to start, then dies when the key is returned to run, you are most likely loosing voltage to the coil. When the engine is turning with the starter, direct 12V is going to the coil from the starter, then when you release the key and the ignition switch goes to run the coil's voltage goes through a resistance wire which drops the voltage to 8 -9 volts. See what the voltage is at the coil, when the key is in the run position. For a test, you can jumper a wire from the battery or starter + terminal, direct to the coil's + terminal, start the engine and see if it keeps running. If it keeps running remove the jumper wire and see if the engine dies, it shouldn't die, but if the resistance wire isn't allowing proper voltage to the coil it will die. (Don't run the engine very long with the jumper wire to the coil or it could overheat the coil, the coil is not supposed to run on direct 12V all the time.)

Points and condenser, just replace them, it's a maintenance item. You have to adjust them properly, a feeler gauge will get you close, but you need a dwell meter to do it correctly. After setting dwell, set the timing.

Go to 4share and download the manual as lbw suggested.