I have a 2003 EFI SN ot790571. At WOT I am getting what sounds like a backfire. Is this possible? If so, what might be some of the causes. I removed the spark plugs and the electrodes were fine on all of the plugs, however, as you look at the motor from the back, the middle plug on the left side had a brown spot on it. I did have the pulse pump and fuel line and bulb replaced from the tank to the motor last year.
A broken reed could cause such a problem in the idle-to-mid range, but would be very unlikely to cause backfiring at WOT (reeds are predominately OPEN at WOT).
Being unable to "hear" the problem, it will be very difficult to ascertain the cause.
I would certainly consider inspecting the plug wires, coils, and a FRESH set of spark plugs. It's a real bummer when you spends days or weeks hunting a problem, and then replace the plugs to find the problem "disasspeared" with something so simple.
Use ONLY NGK: BPZ8HS-10 plugs.
Also possible is an ignition coil that is intermittently firing at higher RPM's.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
I took my boat in for service. I am going to have the plugs replaced, the injectors cleaned, and the reeds replaced. My mechanic recomends sticking with the OEM reeds. Would you recomend the OEM or one of the aftermarket sets?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by X19 Indy »</td></tr><tr><td class="quote">Would you recomend the OEM or one of the aftermarket sets? </td></tr></table>
I am not sure if you have steel reeds in that motor but, if you do, I would get rid of them and go with some type composite reed. Don sells TDR reeds and I just bought and installed some last week in my own motor. I haven't put it all back together yet so I can't provide any results yet but I mainly wanted piece of mind that a broken reed wouldn't grenade my motor!
Most Mercury technicians WILL recommend only OEM Reeds.
That being said... I am extremely pleased with the quality, fitment, and performance of the TDR reeds. I've installed many sets in this engine series... and I think you'd be VERY pleased with the sealing, durability, and performance.
TDR is the "<u>only</u> aftermarket reed" that we recommend or sell.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Thanks Don, do you think there will be any increase in performance with the TDR? Also, I know if a stock reed breakes it can have some real bad effects on a motor. Is there any benefit to the TDR in this senario?
Idle, midrange, holeshot and acceleration will definitely improve.
SOME claim an increase in top end performance.... I do not take stock in this claim, as I feel it is often actually due to the fact that these engines now have a FULL set of sealing reeds (rather than chipped/broken reeds).
TDR's fiber reeds are MUCH safer, should one break. Although they're as (or perhaps more) durable than the factory steel reeds, they're also SOFTER (and would usually pass through the engine with no real damage if they were to break).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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