Another engine not starting, Mercruiser 5.7

[george2064]

New to this forum and you guys are great. I love reading your posts. Here is my problem.

I have a 2001 310 sundancer with two Mercruisers 350 Horizon. I brought it from storage area to the marina and both engines were running fine. It has been on the slip for week.
Now port engine will not start. Having read posts on this forum and having checked for fuel, etc. we seem to be fine except there is no spark coming to the distributor from the coil.

Replaced the coil, there seems to be electricity coming to the coil just not spark. We changed sensor assy in the distributor. Still no spark, it will crank but will not start.

The mechanic things there is a short somewhere. Is that a possibility? How do we find the short?
Any other suggestions?

 

[JediJD]

The quick answer is to check for voltage into the coil and check that the distributor is actually turning and that the cap and rotor are making contact...this is assuming you have actually pulled a plug and see that it is in fact not firing.

Just a hunch, but in my experience primary and secondary ignition gets the blame a lot, when the real problem is fuel delivery or safety shutoffs. You have to have fuel, fire and air. If you have power to the coil, and the engine is turning over...spritz a tiny bit of starting fluid into the intake and see if you get action.

 

[george2064]

Thanks for the quick reply. I will check with the mechanic tomorrow. I think he did try that option. But will double check.

 

[Fun Times]

You could also have him try unhooking the gray wire off the back of the RPM gauge and see if it will start.:wink:

 

[george2064]

Very interesting suggestion... as, I am an engineer, why would that gray wire have to do anything for the engine not starting??:smt100.

Please enlighten me.

George

 

[Fun Times]

Very interesting suggestion... as, I am an engineer, why would that gray wire have to do anything for the engine not starting??:smt100.

Please enlighten me.

George

If the tachometer shorts out internally it will keep the coil from firing a spark, Kind of common, And the gray wire is the signal wire coming from the coil going to the tachometer.

If you look at the coil it should have two gray wires on it One of them goes up to the tachometer.

This is just a normal thing to try in diagnosing a no start/Spark test for boats.

Is your engine EFI or carburetor?

Take a look at this test in this link, Normally the problem can be found within doing a few test like this. Be patient with the link right now, The website is very busy over there right now and it seems slow.

http://forums.iboats.com/showthread.php?t=320755

http://forums.iboats.com/showpost.php?p=2302459&postcount=3

The best way to find your test tree like in the above links is to find your service manual number using your engine serial number, Then do the test out of your book.

PS, That web site has your mercruiser service manual for down load free. It's in the I/O section under the adults only sticky, Then click on number 9 to find your service manuals.

 

[george2064]

Woow cool information I will check it out. it is an EFI engine.

I will get the manuals downloaded as well.

Thanks a bunch :thumbsup:

 

[stuckinforward]

I read thru and always laugh boat Tech, I went thru that 3 day learning curve, good thing i ran into an old timer a few years back...his reply was try removing the gray wire (tach wire) from the coil...cleared right up. I have had 2 of the same since, actually i got a call yesterday with similar problem, i asked the guy if his tach was erratic and the answer was yes....pull the wire and see what happens