liv2ryde100
Active Member
Did u change out the cool fuel covers? Or are they original?
Any Ideas?
- Thread starter sejensen737
- Start date
sejensen737
Active Member
RE:fuel...have always put premium fuel in to avoid ethanol problems
Fuel covers are original but I don't think they are an issue. Fuel rail was clean as a whistle internally and no sign of contamination in injectors when they were cleaned.
Fuel covers are original but I don't think they are an issue. Fuel rail was clean as a whistle internally and no sign of contamination in injectors when they were cleaned.
liv2ryde100
Active Member
The fuel u use has ethanol?
sejensen737
Active Member
negative...no ethanol in premium at marina from what they told me
ColoSR
Active Member
- Apr 25, 2018
- 425
- Boat Info
- 2003 Sea Ray Sundeck 220
- Engines
- MX 6.2L MPI Mercruiser with 2.2 Bravo III drive
My mechanic had to test the fuel pressure on the dyno to figure out my CF2 was going bad. It rev’d up and down fine in neutral, but the pressure would drop to 28-32 psi under load. It was topping out in the low to mid 3000’s rpm and intermittently topping out about 2k.
With the new CF2 it runs like a deer. Only problem now is that about half the time i need to advance the throttle to get it to start. No beeps, but wondering if the IAC is going bad.
With the new CF2 it runs like a deer. Only problem now is that about half the time i need to advance the throttle to get it to start. No beeps, but wondering if the IAC is going bad.
sejensen737
Active Member
Update
Ok guys. Solution!
I finally caved in and switched the cool fuel units. I was avoiding this like the plague due to complications that might arise especially due to the water inlet and outlet fittings. Turns out I had the barbed nipple fittings which are much easier to deal with and wont crumble in your hand as the plastic ones would.
Lots of grunting and swearing but they actually came off without too much drama. I removed the complete muffler system on the port side to gain access. The job would be VERY difficult without doing so.
Once the starboard engine CFM was mounted on the port I did a static fuel pressure test. Pressure held in the rail. Started engine. It ran to 750 rpm and then down to 580. Then hunted for a minute and settled down at 650. Then it ran up to 1200 and settled down to 650 and stayed there. I can only assume that possibly air was being purged from system while it refilled with fuel because all is well now. No more rough running and runs smoothly through RPM range.
I disassembled the suspect cool fuel unit and it was absolutely pristine inside. No paint chips , gunk or corrosion. I jumped the low and high pressure pumps and they ran fine. I blew air through the high pressure pump from the inlet and the outlet to perhaps reseat a stuck return valve. At this point I am highly suspect that that was why the fuel rail was not holding pressure. I put it all back together and will mount it and try it on the starboard engine later today. Might work but if not I'm in for at least a high pressure fuel pump or possibly a new CFM.
Will let you know how it works out...
Ok guys. Solution!
I finally caved in and switched the cool fuel units. I was avoiding this like the plague due to complications that might arise especially due to the water inlet and outlet fittings. Turns out I had the barbed nipple fittings which are much easier to deal with and wont crumble in your hand as the plastic ones would.
Lots of grunting and swearing but they actually came off without too much drama. I removed the complete muffler system on the port side to gain access. The job would be VERY difficult without doing so.
Once the starboard engine CFM was mounted on the port I did a static fuel pressure test. Pressure held in the rail. Started engine. It ran to 750 rpm and then down to 580. Then hunted for a minute and settled down at 650. Then it ran up to 1200 and settled down to 650 and stayed there. I can only assume that possibly air was being purged from system while it refilled with fuel because all is well now. No more rough running and runs smoothly through RPM range.
I disassembled the suspect cool fuel unit and it was absolutely pristine inside. No paint chips , gunk or corrosion. I jumped the low and high pressure pumps and they ran fine. I blew air through the high pressure pump from the inlet and the outlet to perhaps reseat a stuck return valve. At this point I am highly suspect that that was why the fuel rail was not holding pressure. I put it all back together and will mount it and try it on the starboard engine later today. Might work but if not I'm in for at least a high pressure fuel pump or possibly a new CFM.
Will let you know how it works out...
sejensen737
Active Member
Update
Installed reassembled suspect CFM. Fuel pump runs for 2-3 seconds and then shuts off. No pressure in fuel rail. Cycled pump numerous times trying to build pressure but the pump will not prime. Took filter unit off and filled with gasoline. Still won't prime. Attached fuel line to CFM inlet and put other end in jerry can , still no prime. Removed fuel line from pump pressure side , still won't prime. Anyone know of a method of priming these CFM's?
Looks like I'm going down the road of a new CFM. What bothers me is that this suspect unit would pressurise and pump fuel before I took it apart. It just would not hold pressure.
Now it won't even pump which makes little sense to me.
Another interesting tidbit. Low pressure pump is Walbro with "made in USA". High pressure is marked made in Czech. I noticed on ebay a Crotian pump is $70. Mercruiser is closer to $400. But is it the same pump in a Mercruiser box?
Attached Files:
Installed reassembled suspect CFM. Fuel pump runs for 2-3 seconds and then shuts off. No pressure in fuel rail. Cycled pump numerous times trying to build pressure but the pump will not prime. Took filter unit off and filled with gasoline. Still won't prime. Attached fuel line to CFM inlet and put other end in jerry can , still no prime. Removed fuel line from pump pressure side , still won't prime. Anyone know of a method of priming these CFM's?
Looks like I'm going down the road of a new CFM. What bothers me is that this suspect unit would pressurise and pump fuel before I took it apart. It just would not hold pressure.
Now it won't even pump which makes little sense to me.
Another interesting tidbit. Low pressure pump is Walbro with "made in USA". High pressure is marked made in Czech. I noticed on ebay a Crotian pump is $70. Mercruiser is closer to $400. But is it the same pump in a Mercruiser box?
Attached Files:
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sejensen737
Active Member
Final Update (I hope)
New CFM finally arrived. I rebuilt the raw water pump and replaced its hoses due to accessibility while CFM and exhaust system removed.
Installed new CFM and put everything else back together. Put fuel pressure gauge on fuel rail. Ran pump. No pressure in fuel rail. Cycled pump ten times. No pressure. Getting worried. Checked fuel line connections. Ran pump about 10 more times and it finally primed and showed /held pressure in the fuel rail.Started and hunted idle for awhile. Took out for test run and ran flawlessly through all rpm ranges.
As Paul Harvey used to say “and that’s the rest of the story…”
New CFM finally arrived. I rebuilt the raw water pump and replaced its hoses due to accessibility while CFM and exhaust system removed.
Installed new CFM and put everything else back together. Put fuel pressure gauge on fuel rail. Ran pump. No pressure in fuel rail. Cycled pump ten times. No pressure. Getting worried. Checked fuel line connections. Ran pump about 10 more times and it finally primed and showed /held pressure in the fuel rail.Started and hunted idle for awhile. Took out for test run and ran flawlessly through all rpm ranges.
As Paul Harvey used to say “and that’s the rest of the story…”
