HELP! 7.4 Merc dies all of no where!
#21
Registered
Thread Starter
Join Date: Aug 2015
Location: Kansas
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Im gonna try and replace the cheap stuff like coil, sensor, ignition, and kill swiych if that doesnt fix it im.thinking of going with a davis unified ignition.
http://performancedistributors.com/p...-distributors/
I called them.and the tech guy said it hooks up with one 12v and has mechanical advance. There is also another kit sold on ebay i was looking at called mercpromarine8.
http://performancedistributors.com/p...-distributors/
I called them.and the tech guy said it hooks up with one 12v and has mechanical advance. There is also another kit sold on ebay i was looking at called mercpromarine8.
#22
Registered
Join Date: Jul 2007
Location: Port Colborne ON Canada
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
My bet is the coil. Had the one on my 454 Magnum go just like that several years ago. Run the boat for a few hours and it would die at 3000rpm. Open the hatch, check a few things, the coil would cool to a point it would let the engine fire up again.
Changed the coil out, no more problems
Changed the coil out, no more problems
#23
Registered
![Default](/forums/images/icons/icon1.gif)
Are you sure it is not the kill switch?. On two different boats I have had that happen. The part that pulls of the button in the switch would age and loosen up. Go over a few small wakes and it would die. The first one drove me crazy, Years later it happened on a different boat and I knew right away what it was. I now carry a spare.
Padraig
Padraig
#24
Registered
![Default](/forums/images/icons/icon1.gif)
Obviously, this vent should be connected to the flame arrestor or top of the carb. Make sure not hooked to a vacuum source or this will reduce your fuel psi also. Needs to be referenced of atmospheric pressure so the pump can run at it's preset pressure.
#25
Banned
![Default](/forums/images/icons/icon1.gif)
I would take the kill switch out the mix completely for testing - bring a volt meter and a couple of sealed inline spark checkers and go to town with it when your problem happens if it does in fact come back . I would also run this boat on a portable fuel supply to as I said post in # 11.
I would bring a fuel pressure tester also and possible take your mounted fuel rail out of the mix for testing
I had some new mechanical fuel pumps that were installed that overstoked (the arm not manu the exact same as version one ) causing high fuel pressure. Had to shim the fuel pumps for proper fuel pressure as they were dumping too much fuel especially at idle. just saying
I would bring a fuel pressure tester also and possible take your mounted fuel rail out of the mix for testing
I had some new mechanical fuel pumps that were installed that overstoked (the arm not manu the exact same as version one ) causing high fuel pressure. Had to shim the fuel pumps for proper fuel pressure as they were dumping too much fuel especially at idle. just saying
Last edited by BUP; 08-18-2015 at 12:15 PM.
#26
Charter Member # 55
![](https://www.offshoreonly.com/forums/images/icons/charter_member_star.gif)
![Default](/forums/images/icons/icon1.gif)
Too high. should be 6-7 max.
#27
Registered
Thread Starter
Join Date: Aug 2015
Location: Kansas
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
10237297 that is the bolck cast number. I thought you could run either a pump on the block.or newer wuth the gen 6 blocks? Like i said im.completely new to boats and what i know about old carb motors is limited.