1985 merc540 cuts out for a split second then resumes keeps happening

oldfordcrap

Petty Officer 2nd Class
Joined
Jan 11, 2011
Messages
120
hi i have a 42ft eagle excalibur with twinn 540s 650hp apeice was cruisin on lake ontario the other day probley 55mph engines sounded great then one engine cut out completely for a split second tach went to zerothen instantly right back up to 4000rpm like nothing happend then it happend again same thing . the other motor runs perfect. it is just like i turnd the key off for a split second and then back on again it goes right back to where it was now at the dock it is cutting out at idle it has an msd ignition i tried taking the distrib cap and router from other motor and it made no difference still cutting out i am guessing it is a electrical problem where do i start help!!!:confused: any ideas or suggestions anyone thanks in advance
 

NHGuy

Captain
Joined
May 21, 2009
Messages
3,631
Re: 1985 merc540 cuts out for a split second then resumes keeps happening

Since you have 2 of the same motors you can keep swapping stuff til the problem moves. But why not just clean up your electrical connections. Also wiggle the ignition switch and it's wiring to see if it causes the hiccup or stall.
I'd also get into MSD's web page and see if they have a troubleshooting section. You never know if that is a known issue til you look.
If it's not, come back and post your year and serial number.
 

oldfordcrap

Petty Officer 2nd Class
Joined
Jan 11, 2011
Messages
120
Re: 1985 merc540 cuts out for a split second then resumes keeps happening

thanks nhguy i guess there is no shortcuts
 

Rydnlow

Recruit
Joined
Jul 14, 2012
Messages
3
Re: 1985 merc540 cuts out for a split second then resumes keeps happening

I have a 4.3 mercruiser that does the exact same thing and I too am trying to troubleshoot this problem. I have the stock TB IV ignition.
 
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