Plugs for 300x

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10-17-2017, 07:10 AM
65gamblerman

Plugs for 300x

I saw on a previous thread where some are using the NGK BR8IX and NGK BR8HS for 3L motors. Is this a sub. for the 300x motors? I am using the Champion QL77PP now with a rough idle and low end. Any idea if the NGK would help?
Thanks..
10-17-2017, 07:23 AM
JPEROG

I have never been a fan of Champion plugs but the X motors have been quirky when I have run anything else in them.

Joe
10-17-2017, 08:21 AM
XstreamVking

Seems like you have to check the gap on any plug you buy now. Had a 300xs i worked on that was running bad and discovered the gaps were all over the place. Owner had not checked them before installing himself. I set gaps properly, and it ran fine. jm2cts
10-17-2017, 08:30 AM
Go Time

Sorry, double post
10-17-2017, 08:31 AM
Go Time

The QL77PP have always run the best for us in the X motors. And we run them hard.
10-17-2017, 10:09 AM
2jz

Quote:

Originally Posted by JPEROG

I have never been a fan of Champion plugs but the X motors have been quirky when I have run anything else in them.

Joe

:iagree:
10-17-2017, 10:25 AM
PlumCrazy

Quote:

Originally Posted by Go Time

The QL77PP have always run the best for us in the X motors. And we run them hard.

Where do you gap them? Factory spec or something else?
10-17-2017, 10:47 AM
Go Time

There was a service bulletin on them concerning plug gap. I dont have it in front of me, but I seem to remember it was increased to .040... someone will chime in if thats wrong.
10-17-2017, 11:57 AM
vnemous

2001-03 APRIL 2001
Printed in U.S.A. -

2001, Mercury Marine
Page 1 of 1
No. 2001-03
WARRANTY INFORMATION
SERVICE INFORMATION
Correct Spark Plug Gap for 300X Pro Max
Models
All 2001 Model Year 300X Pro Max Engines
Situation
The spark plug gap specification is incorrect on the emissions sticker attached to the engine
and in the Operation, Maintenance and Warranty Manual. The incorrect gap is 0.035 in.
(0.89 mm), which is too wide.
Correction
The correct spark plug gap for the 300 X Pro Max is 0.025 in. (0.64 mm). When checking
or installing spark plugs, set the gap at 0.025 in. (0.64 mm)
10-17-2017, 12:43 PM
65gamblerman

Thanks, that is some good info..
12-24-2017, 09:58 AM
cali kid

Quote:

Originally Posted by Go Time

There was a service bulletin on them concerning plug gap. I dont have it in front of me, but I seem to remember it was increased to .040... someone will chime in if thats wrong.

Beware when gapping a PP. Easy to break off the platnum wafer.
12-28-2017, 07:21 AM
mrcrsr

Br8hs work fine, I wouldn't put champions in a lawn mower! If u run it hard for long periods run the br9hs, I usually gap them to .028-.030. u can use the br8hix, more expensive and an iridium plug.