500 EFI starting issue
#1
"Unregistered Gun"
Platinum Member
Thread Starter
500 EFI starting issue
I have an intermitting start problem with my starboard 500 EFI. First time out yesterday on old fuel but have new separators, boat ran great all day it was around 90 out. Later in the evening I went to start the starboard engine and it would just crank after some attempts it started and ran fine rest of the evening. Well since it was so nice out I ended up taking a midnight ride and ran prob 15 mile at 2800 rpm and ran fine. shut it off for awhile went to start and same thing as earlier in the day, took a little longer to start but once it did it ran great! Any issues with the 500 doing this or good place to start looking?
Thanks
Thanks
#3
"Unregistered Gun"
Platinum Member
Thread Starter
I kind of thought the same thing but have never had any issues the last two years with vapor lock symptoms. Im going to change the separator and fill with new fuel and check some misc things and see what I find.
Could the mechanical pump be weak or loosing prime cause this, even thou there is a electric pump as well?
Thanks
Could the mechanical pump be weak or loosing prime cause this, even thou there is a electric pump as well?
Thanks
#4
Registered
The mechanical pull over pumps on these motors have an oil reservoir that will become contaminated with water and or fuel. It needs to be changed as often as you change your engine oil.
Is your fuel presssure the same on both motors, or is the hard starter lower?
It easily could be bad fuel. Ethanol enchanced fuel does attract water. Did you use a stabilizer over the winter?
Regards,
Steve
Is your fuel presssure the same on both motors, or is the hard starter lower?
It easily could be bad fuel. Ethanol enchanced fuel does attract water. Did you use a stabilizer over the winter?
Regards,
Steve
#5
"Unregistered Gun"
Platinum Member
Thread Starter
The mechanical pull over pumps on these motors have an oil reservoir that will become contaminated with water and or fuel. It needs to be changed as often as you change your engine oil.
Is your fuel presssure the same on both motors, or is the hard starter lower?
It easily could be bad fuel. Ethanol enchanced fuel does attract water. Did you use a stabilizer over the winter?
Regards,
Steve
Is your fuel presssure the same on both motors, or is the hard starter lower?
It easily could be bad fuel. Ethanol enchanced fuel does attract water. Did you use a stabilizer over the winter?
Regards,
Steve
No this was the first winter I didnt use a stabilizer, so im kind of thinking that this might be the problem. I have duel tanks and the other engine is fine!
#6
Registered
I havent checked my fuel pressure yet but going to this week, and I changed the fluid on the pump in Sept. Do I need to check the pressure on the fuel rail or somewere else?
No this was the first winter I didnt use a stabilizer, so im kind of thinking that this might be the problem. I have duel tanks and the other engine is fine!
No this was the first winter I didnt use a stabilizer, so im kind of thinking that this might be the problem. I have duel tanks and the other engine is fine!
I thought your boat probably had dash fuel pressure gauges. Might be a good addition if this persists. I thought Mercury required OEM builders to use them on blue motor installations.
What happens if your fuel pump reservoir gets gas and/or water in it is the eccentric cam wears out, due to poor lubrication and reduces fuel pressure. I have run into it and so have some friends. KE has a nice upgrade for the blue motor mechanical pumps that bolts onto the stock housing, raising volume and pressure.
I'll see if I can find a pic. Bottom right corner.........
Regards,
Steve
Last edited by Steve Zuckerman; 05-26-2010 at 10:17 AM.
#8
Registered
Not one of Merc's better designs. I think they did it because the Gen 6 blocks don't have a mechanical fuel pump mount, like the older Gen 4s (and I think 5s) did, so they combined the seawater pump with the mechanical fuel pump.
Steve
Last edited by Steve Zuckerman; 05-25-2010 at 05:13 PM.