SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: electrowoman on June 08, 2009, 02:25:26 PM

Title: spark plug gap pushed nearly shut??
Post by: electrowoman on June 08, 2009, 02:25:26 PM

My son's boat picked up a miss.  I pulled the plugs for a lookie see and found
a plug with about .010 gap???  No sign of hitting anything thank god... I don't think
I need to hear the top of the piston is leaving the bottom....  There was no sign of hitting
anything either??

Anyone ever have that happen?

Title: Re: spark plug gap pushed nearly shut??
Post by: Mr Plow on June 08, 2009, 03:05:45 PM

Yep!  And then I pulled the heads to find this...........

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi167.photobucket.com%2Falbums%2Fu127%2Fgnx_2%2FMelty2.jpg&hash=986cd8d171e9c2d0a2f46a8b0a78fbee24e5530a) :mad:

Title: Re: spark plug gap pushed nearly shut??
Post by: Marlin on June 08, 2009, 03:30:01 PM

Just got done fixing mine. Had about the same problem. Mine was shaking and missing BAD.

Title: Re: spark plug gap pushed nearly shut??
Post by: CHROMEY on June 08, 2009, 05:08:36 PM

yep!!
see my thread.....
http://www.socaljetboats.com/index.php?topic=6791.0

it could have been a number of things, but its toast reguardless

Title: Re: spark plug gap pushed nearly shut??
Post by: GT Jets on June 08, 2009, 05:12:14 PM

If'n it were me I would go borrow a bore scope and look into your future as an engine rebuilder, the spark plugs can't close their own gaps, something nailed it...Probably a ring land...

May get lucky and had some debris get into the cylinder, but betting not...

GT

Title: Re: spark plug gap pushed nearly shut??
Post by: Ralph Brunt on June 08, 2009, 05:31:38 PM

whats the shiny spot on the other piston ???

Title: Re: spark plug gap pushed nearly shut??
Post by: koyota93 on June 08, 2009, 06:31:50 PM

Here's my old motor.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi59.photobucket.com%2Falbums%2Fg310%2Fkoyota93%2FHoward%2FIMG_2111.jpg&hash=6fc052b5b831780a786db9aeac0ba2871fdd9923)

Title: Re: spark plug gap pushed nearly shut??
Post by: Ralph Brunt on June 08, 2009, 08:07:34 PM

detonation  :o

Title: Re: spark plug gap pushed nearly shut??
Post by: electrowoman on June 10, 2009, 02:17:52 PM

Koyota, do you need another piston to match yours?   I pulled the head for a look see and it's nearly
identical to your broken piston.

I have a new set of flat tops and ordered new rods to beef it up.   It'll be ready in about
5 days counting time waiting on the machine work.

Thank you guys for keeping me from thinking it would be ok  :sly:

Title: Re: spark plug gap pushed nearly shut??
Post by: CHROMEY on June 10, 2009, 03:50:43 PM

lol....thought mine was a bad starter..lol I WAS SOOOOO WRONG!

Title: Re: spark plug gap pushed nearly shut??
Post by: IRRebel on June 11, 2009, 12:56:47 AM

Quote from: CHROMEY on June 10, 2009, 03:50:43 PM

lol....thought mine was a bad starter..lol I WAS SOOOOO WRONG!

Wellll, Really, first you thought it was the pump, as I recall the situation, lol

Funny how these things snowball on yah!

Ray

Title: Re: spark plug gap pushed nearly shut??
Post by: pw_Tony on June 11, 2009, 01:05:31 AM

Just the other week I was helping a buddy dynoing a few bikes. Threw one up on the rollers, and the engine shut off mid pull... they thought it was something electrical, and then I pulled out the spark plug... it complete broke it off  :thumbdown: