Fuel or Ignition Issues After Warm Up

Engines, Shafts, Steering, Struts, Rudders, etc.
Fastjeff
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Re: Fuel or Ignition Issues After Warm Up

Postby Fastjeff » Tue May 17, 2016 5:54 am

Nearly all modern inboards use electric pumps. The "uncool" thing is to wire them so the pump remains running when the engine stops--it's also illegal.

After trying various ways to 'prime the engine' (after it sat a while--the carbs are dry after a week) I installed electric pumps with a bypass switch (to fill the carbs for initial start up). Neat setup!

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

newendeavor
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Re: Fuel or Ignition Issues After Warm Up

Postby newendeavor » Tue May 17, 2016 12:27 pm

That's a great idea. I always hated the wear on my Starters trying to pump gas back into the Carbs after sitting for a week or two. So, I started to use a squirt of Ether to reduce the crank time, but then realized i was washing the oil off my cylinder walls !
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barkleydave
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Re: Fuel or Ignition Issues After Warm Up

Postby barkleydave » Tue May 17, 2016 3:56 pm

Electric fuel pumps must be:

1. Marine Grade and approved for marine use.
2. Wired with a startup bypass to prime carbs(Jeff has lots of info on the setup)
3. Must be wired through an oil pressure switch so pump stops automatic when oil pressure drops even with ignition on.

I have seen the bypass wired through the momentary starter switch when engine starts the oil pressure keeps pump running.

safe boating,
dave
1987 Marinette 29 FB Sedan
Retired Boat Accident UL and USCG trained investigator
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Tranquilo
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Re: Fuel or Ignition Issues After Warm Up

Postby Tranquilo » Tue May 17, 2016 4:01 pm

Any chance the oil pressure switch is glitching out and killing my ignition?

I guess if I jump the coil to the battery, I'll have a better idea
2x 1973 28 Express - Single 318
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Miami FL & Catawba OH

barefoot99
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Re: Fuel or Ignition Issues After Warm Up

Postby barefoot99 » Tue May 17, 2016 5:09 pm

Jeff any chance you can post the bypass setup Sounds like my next project ....

Thanks in advance -Scott
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Fastjeff
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Re: Fuel or Ignition Issues After Warm Up

Postby Fastjeff » Wed May 18, 2016 6:28 am

You'll need an oil pressure switch with a set of normally open contacts (that close under oil pressure--the opposite of the present oil pressure switch). I found a 1990s era Mopar oil pressure switch that did the job.

The wiring is fairly straight forward: The FP ground goes through the above switch, with the ground wire also going to a momentary switch at the helm (and then to ground). Power to the FP came from a relay I wired into the ignition circuit to trigger it. Battery voltage was used to power it. (The relays are available, cheap, on E-Bay. Look for 'Bosch-type' 12 volt relays with the wiring connector.

Sorry, but I don't have a schematic.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

Tranquilo
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SOLVED: Fuel or Ignition Issues After Warm Up

Postby Tranquilo » Mon May 23, 2016 8:39 am

Issue was solved by reinstalling the fuel system up to the carb. Removed a bunch of old copper runs and shortened the system by several feet.

My electric pump was installed at an upward angle. I made it horizontal and the fuel pressure remained in a suitable range for my runs over the weekend. I still see it drop as low as 3psi when getting to 3k. I have a backup pump in case the pump is damaged and craps out eventually.

I installed a fuel pressure regulator, gauge and new filter. Added the Techtron stuff to my fuel
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH