Mercury 90 EFI 4 Stroke - Starting Problems

[hagonzal]

Hi all,

I have a 2005 17 Montauk, with a 2006 Mercury 90 EFI 4 Stroke. I am having problems starting the engine. Sometimes (maybe 4 out of 10 attempts) when I turn the key in the ignition, I hear what seems to be the fuel pump in the engine, but it does not start. The engine does not try to start, sometimes it makes absolutely no noise, and sometimes it makes a single click type of noise. After I try a few times the engine starts. But it never cranks slowly or abnormally, it either starts, or not starts.

I initially thought that it may be the battery, or battery terminals, but after buying a new battery and replacing the nylon nuts that lock the terminals, the problem persists. I also thought that it could be the safety mechanism that prevents starting the motor while in gear, but jiggling and moving the control does not seem to have an effect on the problem.

Any ideas on what could be the problem? Also, does anyone know which service manual from Mercury covers this model?

Thank you
--Hector

 

[jbrown270]

Re: Mercury 90 EFI 4 Stroke - Starting Problems

starter solenoid is going out which makes a "click" sound or it could be a loose wire somewhere. sometimes you can tap on the solenoid with a screw driver and get it to work.

 

[cloonkeen]

Re: Mercury 90 EFI 4 Stroke - Starting Problems

I have the exact same problem on basically the same engine.

http://forums.iboats.com/showthread.php?t=320516

 

[JB]

Re: Mercury 90 EFI 4 Stroke - Starting Problems

First, remove and clean up all connections of battery to engine cables, Hector.

 

[hagonzal]

Re: Mercury 90 EFI 4 Stroke - Starting Problems

This morning I did some further investigation. I removed the cowling and a cap that covers the flywheel. When I turn the ignition switch on, and the engine does not start, what happens is the following. The click that I hear is the pinion gear engaging with the flywheel. After engaging, the starter motor does not turn. I then turn the key again, and the pinion gear turns.

I checked battery connections, both at the battery and at the engine side, and everything seems tight, I re-tightened things to make sure, but the problem persists. It is quite hard to diagnose as many times the engine starts fine.

Given that the pinion gear engages the flywheel, I think that they are getting power, and that the ignition switch, and neutral safety switch are probably working ok.

Thanks

 

[JEFFYAX]

Re: Mercury 90 EFI 4 Stroke - Starting Problems

Sounds like the same symptoms i had with my 2008 60hp 4 stroke.
I also swapped the battery...that wasnt it.
Then i tried the keyswitch several times, on,off,on,off,on,off. I probably did this about 25 - 30 times. I could feel that the contacts inside the switch were slightly corroded. Finally I connected the switch to the wire harness and it worked.
Before doing this, the audible beep was hit and miss. Now it works fine.
The next day i went to the marina and bought a new switch asm for $23
and replaced it. took all of 2 minutes to replace. I havent had a problem since i changed it 6 weeks ago.

Hope this helps.