Ohh great sea-doo spark plug readers guild. bestow upon me your knowledge.

[SabrToothSqrl]

So my friend and I rebuilt my 951 engine. runs 90% sometimes, sometimes 100%

sometimes it pulls HARD and shoots to 7,000 RPM, sometimes not so hard and 'pauses' at 6,000 RPM.

compression is 100 each side, rave sliders are new, airways clear, and parts clean.

impeller is new, as is wear ring (new before engine failure).

my engine also seems to be running hot, but as my wife destroyed my other ski I have nothing to compare it to.

Attached are the plugs after a few runs, one is noticable ligher than the other.

Do i richen up the lighter plug (rear of ski side) or lean out the darker one?

I put in brand new plugs, ran wide open, did the shutoff/throttle off, pulled the plugs, and even after FOUR tries, they look brand new!

the oil pump works, and was tested, cable secure and opens it, (I'll triple check wednesday night), but hooked to a cordless drill and it pumps oil...

this is tank #3 for the new engine. first tank had added oil for break in.

the ski will sometimes hit 7k and pulls great, sometimes... 6k pause and not so great.
water pressure reg is 100% as well. (I just rebuilt it).

So, my guess now is it's lean wide open, and not getting the fuel it needs to pull hard up to 7k off the line...

please bestow upon me your mad spark plug reading skills, and help me find how to adjust these things... I do have the 2002 OEM 600 odd page PDF as well


CFL + Iphone do not make for good photos, but the one is a light grey, the other is a hair lighter...

I guess I should err on the side of too rich, as that will just foul plus vs overheat and destroy my engine.

 

[LouDoo]

I can tell that you're right handed, you took this over a white piece of paper in your parents basement, its slightly out of focus, and they came from a 951 engine. LOL

Seriously they look pretty good to me, like you said a little rich, its really kinda hard to tell, I would re-install the plugs and run them for a couple more hours and have another look. So far the one on the left on the first pic. looks perfect.

Lou

 

[SabrToothSqrl]

Nope, my kitchen table

You think the one on the left (leaner) one looks better?

and that's NOT my purse in the background... it's the wife's who killed my other ski...

 

[Dennis]

I would richen up the lighter one. Where are the needles set now? Stock jetting and air box? And yes, always error on the side of too rich.
The darker one looks about right for a high speed run and then shut off. If it looked like that after a hour ride that included all rpm and speed ranges then I would say it should be a little richer also.

 

[SabrToothSqrl]

that's what i'm thinking.
they are 100% factory spec and my ski is 100% factory (solas impeller).
these plugs are about 3 tanks old... so it could be lean throughout the throttle range... the low speed looks fairly easy to get to on the 951, the high speed looks really 'fun' to get to...

 

[Dr Honda]

In my opinion... on a high output 2-stroke... I would like to see them darker. A little extra fuel cools the combustion chamber, but too much overheats the exhaust.

BUT... they are OK.

Don't adjust the low speed screw. The low speed screw is ONLY for setting the idle fuel. It has almost no effect once you crack the throttle since the pilot jet feeds the needle. SO... you can only get as much fuel as the pilot jet will give. If you need more low to mid fuel (up to about 1/3 throttle) then you need to put in a larger pilot jet.

OK... think of it this way.......


The pilot jet feeds the low to mid fuel. BUT... at idle... the vacuum is very high, and it will go EXTREMELY rich. So... the low speed screw is to lean out the idle fuel.


Now... the high speed screw is just the opposite. The high speed screw, and the main jet have separate fuel feeds. SO.... if you need more fuel up top... you can open the needle, and you will get more fuel that the Main jet can deliver.

If that was my ski... I would make sure the oil pump is set up properly... and open the high needles about 1/8 more than they are now.

 

[Dr Honda]

Here's how dark I would like to see an 800 or a 951.

 

[LouDoo]

Hey Sqrl,

I was kinda going by a chart that SeaDooSnipe posted, you can check it out here. Just scroll down a couple of pages. Check out no. 14.

http://www.seadooforum.com/showthread.php?4151-Snipes-Korner...

Lou

 

[dunne]

I am curious about your compression, is it 100psi after 3 tanks of fuel or before and how many hours should it take to seat rings after a top end job to see the 135 to 150 range. I am not saying you have a compression issue just wondering what the opinions are on that.

Phil

 

[SabrToothSqrl]

thank you everyone for the help, i hope to adjust and get on the water with new plugs tonight.

i think it was 110 when the engine was 'new', i'm not sure if the guage is off or what, but we have some widly variable results for compression on here... I think starter speed also can affect it... mine is 9 years old with a 2 year old battery, and the ski does run 7,000RPM, but like the above posts, I will attempt to open the rear high speed screw 1/8 turn and see what happens... those are some dark plugs above! maybe both need a hair out once i get them 'even'... or 1/4 rear and 1/8 front turn...

my main 'discovery' with the compression guage is 1. are both cylinders the 'same' or within 5 psi, and are both over 90... because i've had them as low as 70 before (problem).