• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter

Plugs question

ellj

Well-Known Member
Messages
39
Reaction score
11
Points
57
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
19
What is normal plug color and is this it?
 

Attachments

  • 20220705_153458.jpg
    20220705_153458.jpg
    961.7 KB · Views: 24
Last edited:
What did the end your holding specifically the electrode color look like?
 
The bottom of the plug might be helpful to see also.

Are you seeing normal max RPM?

Perhaps your pressure gauge was just not cooperating on that cylinder?

If compression is still zero, I would suggest trying SeaFoam spray on that cylinder in case you have a stuck valve that might loosen up, but zero compression and running engine on something so new is a rare ocurrence.
 
The bottom of the plug might be helpful to see also.

Are you seeing normal max RPM?

Perhaps your pressure gauge was just not cooperating on that cylinder?

If compression is still zero, I would suggest trying SeaFoam spray on that cylinder in case you have a stuck valve that might loosen up, but zero compression and running engine on something so new is a rare ocurrence.

Plug here20220705_151449.jpg

Yes, RPMs and MPH appeared normal during water test but I can re-test.
 
Last edited:
If RPM and Speed are normal, no need to mess with it, the engine is fine.

If you were trying SeaFoam intake spray it actually goes in the intake while the engine is running. Instructions on the can.

You don't need it. If you are reaching max RPM and speed, you are not on a 0 psi cylinder .
 
The plug looks wet, like it is not firing. Can you pull one of the other plugs to compare? How old are the plugs?
 
If RPM and Speed are normal, no need to mess with it, the engine is fine.

If you were trying SeaFoam intake spray it actually goes in the intake while the engine is running. Instructions on the can.

You don't need it. If you are reaching max RPM and speed, you are not on a 0 psi cylinder .

I thought normal psi was like 140ish.
 
Last edited:
The plug looks wet, like it is not firing. Can you pull one of the other plugs to compare? How old are the plugs?

Plugs are about a year old

20220705_150549.jpg

That's off CYL1
 
Low compression engine generally does not make max RPM and max speed.

Can you confirm your methodology for testing? Did you open to Full Throttle? For how long did you crank? Did you take more than one reading? Did you remove other spark plugs?
 
Cold engine

Removed spark plug only from one cylinder

Screwed in tester

Removed safety lanyard

Cranked key until pressure gauge wouldn't go up higher

FUCK was I supposed to put throttle to max and didn't? And all spark plugs out before testing? ?
 
Last edited:
Looks the same. I assume the compression test was a cold one. If you are pulling the RPM's you are supposed to, your good. You will hear and see a misfire on the tach.
 
No need to remove all the other plugs but It can affect your reading slightly.

Throttle position definitely affects your reading, and would show much lower without full wide open throttle .
 
No need to remove all the other plugs but It can affect your reading slightly.

Throttle position definitely affects your reading, and would show much lower without full wide open throttle .

Thanks, I'll retest.
 
Back
Top