'06 4.3L Mercruiser Won't Start After Doing Engine Maintenance

[GIJeff]

Hi all,

I have a 2006 Tahoe Q4 Sport w/ a 4.3L Mercruiser engine (carbureted) and it will not start. It will turn over (most of the time) but if it starts it immediately stops. This just began happening yesterday.

It has worked fine up until this incident yesterday. After the last time it ran fine (few weeks ago), I did a bit to the engine and wonder what I did that could have messed things up. Here?s how I got to this point:

-I replaced my front seal, so I had the crankshaft pulley & harmonic balancer off. For better access, although completely unnecessary, I pulled off the pulley for the water pump, also.

-I attempted to repair a leak where crankshaft position sensor goes. I assume the O-ring is failing because it was leaking out of that hole, so we covered the sensor w/ Ultra-black Loctite and put it back in there. Oil still leaks so I?m going to purchase a new O-ring and try again. Any advice on this silly little leak would be nice, too!

-I completely cleaned and degreased the engine. I had the air filter off because I was cleaning it separately, so I covered the opening to the carb w/ a plastic bag and also covered the alternator. The rest of the engine, I sprayed down completely w/ degreaser, let it sit, then hosed it all off.

-I did not run the boat at all after cleaning it until I headed to the lake. When I first put in the water, I tried to start the engine. On the first turn of the key, the engine wouldn?t start. I tried to turn it again and it stopped turning over, as if the battery was dead. I assumed the battery was the problem. I tried to turn the key a few more times and all the boat did was ?click.? The engine didn?t turn over or anything. I had my fianc? pull me a few feet out of the water, I tightened all of my connections to the battery to make sure I had a good connection, and I turned the key again. Engine started. Back in the water.

-I have a common problem where when I first put in the water and get on the throttle hard, the boat falls flat. Separate issue (I assume) that I just haven?t dealt with yet. As long as I ease on the throttle to get it up to full speed the first time, the rest of the day is always smooth. This time, it seemed to be idling a little rough, and it was really touchy in regards to throttling up for the first time of the day. I had to take it very slow and slowly move the throttle forward. Got going, went WOT for about 5 min, then I came to a stop to put my wakeboard on, engine still running. After idling for another 5 minutes or so, the engine just stopped.

-I tried to restart the engine, and it wouldn?t start. Most of the time when I turned the key, the engine would turn over it just wouldn?t spark. Every now and then it would almost start, but then it sounded like it stalled. Pulleys stopped turning and the engine made a strange sound and stopped turning over. Sometimes when I turned the key it would just click. Sometimes when I turned the key it would sound like the battery was dead/near dead and wouldn?t do much of anything. I let it sit for a minute, tried starting it again, and a couple of times I got it to start for split second but then it would die.

-Towed to shore, pulled it out, and bought some Heet to put in the gas tank and some starter fluid to spray in the carb. Tried hooking it up to muffs and starting it on land using the starter fluid, wouldn?t work. Essentially did the same thing as it did in the water. It almost started a couple of times but then immediately died.

Any idea? I thought I may have gotten water (or degreaser) somewhere in the system while I was cleaning the engine, but why would it have ran for 10 minutes or so and then died?

 

[GIJeff]

One more thing, I noticed there was a very light amount of smoke coming off the engine, more towards the back of the compartment. I couldn't identify where from. Perhaps this was just water burning off from where I had sprayed it down recently, or something more serious?

 

[alldodge]

You keep having the issue of a "click" and sometimes after tightening the battery cable it will start. Suggest removing both end of the cables, positive and negative, and clean and get some shinny metal. Inspect even the cable going into the clamps and ends for corrosion. Get rid of the wing nuts on the battery and put some washers and nuts. Find your slave solenoid and clean those terminals also.

Lets us know what you find

 

[Bt Doctur]

Only time I give it a bath is when I`m taking it to bed, what is it with all the motor cleanliness?
you cover the alt and the intake, what about , the main breaker, the slave solenoid, etc, etc, etc.

 

[GIJeff]

The "click" issue has occurred before, however the boat has always ran in the past and this problem of not starting is new. I've had it out 6-7 times this year already. In the past, on rare occasion I would turn the key and just get the "click," but turning the key a second time would make it start just fine without making any changes or adjustments to any connections.

Now, sometimes when I turn the key it does the "click" and doesn't turn over, but turning the key again will make the engine turn over and attempt to start, leading to the other list of issues I mentioned - starting for a split second then dying, will stop turning over and "stall," or act like the battery is dead and stop trying to turn over.

Slave solenoid - can you explain this to me? I should've prefaced this story by saying I have almost zero mechanical knowledge, I'm just learning as I go and trying to soak up as much from the forums and do as much work myself as I can!

I will definitely clean up my battery connections, however I don't think that will solve the part of it turning over and not starting. I have nuts/washers and I cranked them down pretty securely yesterday after the initial problem during put-in.

 

[Bt Doctur]

almost all boats use a "slave" to have the main solenoid on the starter activate. This is because the solenoid draws too much current for the 16Ga wire . slave usually located with/near the 50 Amp breaker.
has a small yellow/red wire, a small black wire, a large yellow/red wire and a large red purple wire
From the key, to the slave, to the starter solenoid.

 

[Bt Doctur]

the part with the black plastic cap on it

 

[alldodge]

It looks like the one in this link, they go bad periodically
http://www.amazon.com/STARTER-SLAVE-SOLENOID-GLM-Number/dp/B004AR1F4E

 

[GIJeff]

Only time I give it a bath is when I`m taking it to bed, what is it with all the motor cleanliness?
you cover the alt and the intake, what about , the main breaker, the slave solenoid, etc, etc, etc.

I had an oil leak and my entire engine and compartment was filthy. Cleaned the entire thing to help identify the leak and to just clean it.


Thanks both of you for the help - for inspecting and cleaning the solenoid, should I just remove each connection, clean it up, and reconnect each wire? Anything else involved in that? This is probably a silly question, but where do the other ends of my battery connect to? I'll make sure they are connected securely to the battery, but the other side...?

I did not cover the solenoid or main breaker when I was cleaning the engine.. could water have gotten somewhere it shouldn't have? All I covered was the alternator and the carb intake.

So I'm assuming this will help in regards to the starting issue, but what about why it died initially? I had it running, then it just quit and won't restart.

 

[Bt Doctur]

the pos red cable may go to a battery selector switch or directly to the main lug on the starter.The black negative usually goes to a stud on the rear flywheel housing cover.
Guessing its a GEN V ign so any of those plugs getting wet can kill the engine. You will have to determine if you have spark or not first.
A quick test is to jumper the 2 large lugs on the slave to see if the starter spins, No= a poor connection

 

[GIJeff]

the pos red cable may go to a battery selector switch or directly to the main lug on the starter.The black negative usually goes to a stud on the rear flywheel housing cover.
Guessing its a GEN V ign so any of those plugs getting wet can kill the engine. You will have to determine if you have spark or not first.
A quick test is to jumper the 2 large lugs on the slave to see if the starter spins, No= a poor connection

Ok just so I understand - connect terminals A and B in the diagram above w/ a piece of wire and see if it does anything? If it does, the slave solenoid isn't a problem - if it doesn't, I need to fix the connections on the solenoid?

 

[Bt Doctur]

A and B together will make the starter operate and spin the motor if the battery, battery cables, etc are connected and in good condition.
If nothing happens then you may not have 12v at the red wire. or the starter solenoid is bad. Go to the starter and jump the main battery post to the small lug with the yellow/red wire. starter should operate, if not solenoid or starter is bad.
Post the results

 

[GIJeff]

No Title

Update: engine started, idled for 5-10 min, then died and won't restart. I decided to just turn the key a couple times before going any further in the troubleshooting. First time, engine barely turned over as if battery was dead. Second time, engine turned and turned over repeatedly, but wouldn't stop. Once I released the key, the engine "hiccuped" and shot a jet of gas out of the carb. Third time, engine started. I think I may have figured out what happened - I pulled off the air filter to clean it, but I bet I didn't clean it very well and loosened debris was sucked into the carb once I started running it afterwards. I looked inside the carb and noticed there was some black debris in the top. See attached pic. Hard to see, but the smudge in the middle is where I rubbed my finger on it.

 

[GIJeff]

I just jumped A and B and the starter kicked on and turned the engine over. Won't start again, unfortunately. I really think my carb sucked in debris from the dirty air filter.. I shook the thing earlier and little black chunks of gunk fell out.. Just like I rubbed off the inside of the carb. Any way to clean this without pulling the thing apart? What kind of damage could all of that gunk do?

 

[alldodge]

I just jumped A and B and the starter kicked on and turned the engine over. Won't start again, unfortunately. I really think my carb sucked in debris from the dirty air filter.. I shook the thing earlier and little black chunks of gunk fell out.. Just like I rubbed off the inside of the carb. Any way to clean this without pulling the thing apart?

No, you have to take it part to clean it. Flakes of stuff on the outside of the carb can do no harm. They get sucked in a spit out the exhaust.

What kind of damage could all of that gunk do?

Junk outside the carb of no issue. The junk on the inside of the carb can cause the engine not to run. This same junk also has a possibility to cause a lean condition and if that happens you might be rebuilding the engine

 

[GIJeff]

Well that doesn't sound good.. next step - remove the carb and clean it? Is this something someone like myself with little mechanical skills can do with a little research and instruction?

So that is possibly the issue w/ the engine not starting/staying on, right? What about the other issue, where the starter sometimes just "clicks" instead of turning the engine over? What would the next step be there?

Thank you all for the help!

 

[Bt Doctur]

a bad starter solenoid or a low battery can cause the contacts to stick together . This makes the starter run continuously.
If you have soft clicking and you short A and B and it runs, you have a bad slave solenoid.

 

[GIJeff]

Got it. Pulling the carb this weekend to clean, and will replace the solenoid. Item #21 on this link, correct? http://www.boats.net/parts/search/M...HRU 0W649999/Electrical Components/parts.html

 

[alldodge]

Got it. Pulling the carb this weekend to clean, and will replace the solenoid. Item #21 on this link, correct? http://www.**********/parts/search/...HRU 0W649999/Electrical Components/parts.html

Your link did not work, use mercruiserparts,com to find it