Guys,one thing I don’t quite understand. Everybody is saying to spray the plugs with some type of solvent and let it soak in. That compressible ring on the plugs is a seal,it prevents exhaust gas and compression from leaking by the plug. If it can hold 90-100 psi of compression then how is anything gonna soak by it? Seems like the best way to soak it would be remove the heads and soak from the bottom,the threads themselves are not sealed and solvent would soak by them.
You are 100% correct. If worried about ruining the threads then get a bigger ratchet and just break them loose then put the penetrating oil to them. They will come right out.Originally Posted by Rip Bass
Proud Army Dad
The heads can be repaired with Heli coils if you damage the threads.
99' 201 Pro Elite
08' Evinrude 225 HO
Although the spark plugs have a gasket I'd still use a penetrant. If I'm not mistaken Ford does a similar process with their stuck plugs. I'd use a penetrant, what could it hurt? I believe the oils will get around the gasket if it is possible over time and through a heat cycle. A hole gets bigger when it gets hot, and aluminum expands faster than steel. That's why you warm the engine if you encounter trouble.
As far as Helicoils, they don't always stay where you put them.
My thoughts are that there may be opportunities for the penetrating oil with no apparent significant risk and potentially tremendous reward. Not sure what the involved tolerances are but given the general nature of outboards and that Ficht spark plug indexing supports a variable torque range dependent on the plug index mark relative to the injector, perhaps the crush washer is not as crushed as one would expect...
Last edited by Neverest; 07-16-2018 at 03:35 PM.
Update: Kroil performed as expected.
All but one of the plugs came out with minimal effort. I suspect the odd-ball difficult one was over-torqued in an attempt to properly index the plug and it still wasn’t properly aligned with the injector. All plugs were Champion QC12PEP and had gaps ranging from .040 and .050 with various lengths of remaining center electrode. I regapped them all to .030 and maintained their original indexes for impending decarb with BRP Engine Tuner, then I’ll replace them...
Last edited by Neverest; 08-02-2018 at 06:12 PM.
When you install the new plugs gap them to .028 makes them last a little longer. For better plug life, change the thermostats to the etec ones and run the irridium plugs.
Will do sir. I plan to upgrade the plugs/thermostats next time - have already ordered a dozen of the PEP plugs presuming I can get six to properly index (I'll gap them at .028). Also going to clean/replace the exhaust pressure sensor after the decarb. Thru observation, can I determine if the ETec thermostats are already installed? I'm presuming I have the OEM thermostats based on the preexisting PEP plugs. Thanks...
Last edited by Neverest; 08-03-2018 at 07:34 AM.
Closer gaps do not make them last longer, Closer gap will increase plug fouling problems and will not ignite a lean mixture as well. Set to manufactures specs, you will be far better off
Thank You Leon Pugh
Actually on the Evinrude DFI motors it will. The fuel flow is controlled by the motors computer. The added .002" tighter gap aides in the plug life on this motor when extended time is spent idling graphing a location and the change in the thermostats allow the owner to switch to an Iridium type plug allowing the switch over from the conventional copper plug.
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