boat not starting???

[gunnymartin]

I have an I/O mercruiser 3.0l 4 cyl that will not start. I am really new to boating, but cars I know (I only say that because I understand engines). The straight 4 wont turn over. The battery clicks the starter pushes and the whole engine rocks 1 time on the mounts, but that's it. I'm used to the starter turning it over several times until the sparks ignite and the engine runs. If I hold the key in the start position it will hold the engine in the rocked position like the starter is trying to turn the engine over and it won't go. Then if I let it off the engine falls back into place. It's like something is seized between the starter and the engine..... I tried to drain some oil and put it back through the engine because it's been sitting a while. Of course the guy who sold it to me said it ran fine. It's been winterized and sitting for about 2 years. I tried starting it with the earmuffs on and the garden hose running to save the impeller..... someone's advice to check it before the maiden voyage. Bottom line all I get when turning the key is the engine rocking up about a 1/4 inch, the crankshaft turns about 1/4 inch and it holds as long as I hold the key over. If I let go it goes back. Somethings stuck. Advice?????????

 

[Don S]

Re: boat not starting???

Pull the spark plugs and see if there is water in the cylinders. AKA Hydrolock.

If no water and it still does it with the spark plugs out, remove the outdrive and try again.

 

[gunnymartin]

Re: boat not starting???

I'm pretty smart and pretty well mechanically inclined, but I am not sure what a harmonic balancer is. as I sit in the drivers seat looking back at the motor I see three pullies. One is the alternator on the far right. the other is the lowest of the three which from all i can tell about the layout of the engine is connected to a shaft that is connected on the other end to the flywheel where the starter gear is. then the third is a pulley on top that looks like its the cam pulley????

Anyway here is where I am now and what I have tried. I pulled the sparkplugs and poured a little motor oil in there and I'm letting it sit after WD40 didn't work. I tried to figure out a way to turn the lower pulley that appears to be attached through a shaft to the flywheel. The problem is the motor mounts are in the way. I'm working in my driveway, so I am trying not to pull the whole motor. The leverage was poor and there doesn't appear to be a bolt of any kind to put a socket on. I don't want to start prying at things until I know what I am doing.

I pulled the starter to try to get it tested, but the autoparts store won't do it because it's from a boat. Anyway the starter is back in and the symptoms haven't changed. When I turn the key all three pullies slightly move and the belt gets tight, which gives me the idea that the starter has to be putting tention on the flywheel to get it to turn.

I'll follow your advice by not using the starter anymore. Thanks.

Someone told me to use a breaker bar. That provided very little area to turn as well as not having anything to attach it to. The crankshaft pully doesn't have anything to attach to. Is there any other way to get it to turn? Is there a way to get to the flywheel side of the crank to turn it??????

I'm going to go digging around to see if I can figure it out, but I'll only go as far as common sense allows.

 

[gunnymartin]

Re: boat not starting???

Pull the spark plugs and see if there is water in the cylinders. AKA Hydrolock.

If no water and it still does it with the spark plugs out, remove the outdrive and try again.

Am I understanding you right? Should I pull the plugs, and try to start it with no plugs in?????

By the way, there was no water in the plug holes when I first pulled them. Now there's a little oil in there, but water free.

 

[Don S]

Re: boat not starting???

Am I understanding you right? Should I pull the plugs, and try to start it with no plugs in?????

Of course it won't start with the plugs out, but it may TURN OVER and push water out of the spark plug holes which would be an indication of a hydrolock.

 

[oops!]

Re: boat not starting???

the harmonic balancer is the main crankshaft pully.

the lower pully that has the belts on it.
in the center of that pully is a big bolt.......put a big socket on it and with the plugs removed, try to turn the whole crankshaft.......(the belts will turn and everything will turn...hopefully)

 

[Zackman]

Re: boat not starting???

Sounds like you need to do step two in Don S's original post (post #2), which is to remove the drive and try to start it again with the spark plugs out. The drive could be the problem... Sounds like the starter is (or at least was) fine.​