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IceinWI
09-11-2006, 01:56 PM
'06 325hp EFI engine with ~40 hours

2 known issues: speratic noise/knocking over 3500 rpm with engine under load.

Hopefully issue is leaning towards bad fuel. (always used mid-grade or premium in 1 case)
With transmission locked out, revving engine alone never produces noise, however accelerating over 3500rpm or constant running over 4k produces the random knocking/popping noise. Almost sounds like a back-fire even.

Other issue was discovered while investigating noise above, and that is sounds like a lifter is sticking to one of the cams as there is a metallic clicking noise relative to engine speed. Fluids have been checked regularly and proper engine break-in and 20 hour service were followed correctly. This noise may have been present before, but wasn't noticed till the ears were perked up looking for problems.

Thanks for your thoughts and advice!
Erik

BensonWdby
09-11-2006, 07:20 PM
No so sure about the gas. All I use in my 99 5.7L Carb is unleaded regular.
Shot-in-the-dark: Try lowering your octane??
Dave

gotmyboat
09-11-2006, 08:21 PM
I have heard that using gas that is higher in octane can cause pre-ignition. The air/fuel mixture ignites from the heat of the cylinder, before the spark, which can cause backfiring. I have an '05 with the 325 EFI and I have only used 87 octane. Not a single problem here. Give it a try. If not the gas, then let the warranty work for you.

Good luck,
Dave

Engine Nut
09-11-2006, 08:51 PM
Originally posted by IceinWI


'06 325hp EFI engine with ~40 hours

2 known issues: speratic noise/knocking over 3500 rpm with engine under load.

Hopefully issue is leaning towards bad fuel. (always used mid-grade or premium in 1 case)
With transmission locked out, revving engine alone never produces noise, however accelerating over 3500rpm or constant running over 4k produces the random knocking/popping noise. Almost sounds like a back-fire even.

Other issue was discovered while investigating noise above, and that is sounds like a lifter is sticking to one of the cams as there is a metallic clicking noise relative to engine speed. Fluids have been checked regularly and proper engine break-in and 20 hour service were followed correctly. This noise may have been present before, but wasn't noticed till the ears were perked up looking for problems.

Thanks for your thoughts and advice!
Erik

89 octane is the fuel that we recommend. 87 is OK as long as it is fresh. I would have your dealer connect his laptop and ask him to check the cam angle. It is supposed to be 705 degrees. If it is too far off, you will get cross firing in the distributor and it could create the symptom you are describing.

The clicking noise is most likely the fuel injectors. They tend to be a little noisy and the noise changes with RPM. On your engine they are pretty exposed so the noise is more noticible than on the 340 MPI. I would have the dealer technician listen to see if the noise is normal or something that they have not heard bfore.

Engine Nut

BensonWdby
09-11-2006, 10:15 PM
Larry
Thanks for clicking in.
What kind of problems might we see if we run 87 Octane, and how old does gas have to be to be considered non-fresh?

Thx
Dave

IceinWI
09-12-2006, 01:58 PM
thanks for the replys!

I thought it was gas that had a lower octane could pre-ignite (knock), as the higher octanes are used with high comp ratios engines?

I've used 89 octane all but one time (which i believe is the tank that i'm just about finished with) when the pump didn't have mid-grade, and i didn't feel like mixing as i wasn't sure how much was in the tank at the time, and from what i remember about the indmar manual, (good bathroom reading) it said 89 minimum, so i figured the 91 would just be more $ out of the pocket but no problems/knocking.

I'll be at the dealer this Sunday so I'll have them take a look at the cam angle and listen to the fuel injectors.

thanks again guys,
Erik

Brian Raymond
09-19-2006, 11:29 PM
Erik, have the dealer check/replace the fuel filter. When these get full of crud, it can lean the motor out and cause popping at higher rpms., yet run okay mid range. Looks like ya got 'er licked on the tickin'. keep us posted. Brian Raymond