- Location
- San Diego, California
Any info would be appreciated thanx
Help reading plugs?
- Thread starter 01jetsurfer
- Start date
Any info would be appreciated thanx
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
how old are they?
- Location
- San Diego, California
three sessions about an hourand half each over a weeks time
They look normal for an NGK no.8. That doesn't mean much since you could still be jetted too hot at full throttle and they darken instantly with the typically rich part throttle settings. My plugs end up dark brown, sometimes black with a peaked out WOT and the pilot rich enough for best response.
- Location
- Saginaw MI
I think they look pretty good, safe rich but not wet at all. What’s the problem?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
SXIPro
JM781 Big Bore
- Location
- Here on the 'X' mostly
Mine pretty much never look that clean besides when I take them out of the box.
- Location
- San Diego, California
since i rebuilt the carbs it has not been running the same im trying to tune the carbs without knowing what a perfict running superjet sounds like. but im getting all kinds of random things happening like mid throttle bog. when i take it out of the water and start it the engine revs extreamly high like it running away and only way ito stop it is to kill it. i turn down the idol screw and it wont start in the water. when i shut it off i have to really crank it to start it again. neetle and seet are new 1.5 alonfg with the carb kit oem pop off at 35 both carbs primer no choke butterflys and no screens i didnt look what the high s and lows were when i had them out i should have but didnt . next time ill look. i feel like im chasing my tail with these hi and low screws and getting it to idol . does all that sound normal idk
Loads of wisdom located here: http://www.groupk.com/tec-carbs98.htm
- Location
- Saginaw MI
You might have messed up one of the new needle and seats when you installed them? Sounds like your out to lunch and especially after a rebuild something must have gotten missed. You shouldn’t be chasing like that if things are how they should be. Maybe pull carbs and go Over it all again
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
The low screw is for idle only! The top is for full throttle only! Set the low screw on the trailer. Set the top by getting the best pull at full throttle. Open the top until power is lost and close just enough to restore best pull. For idle do the opposite, close the lower screw until the engine races then open until it slows down. Part throttle should sputter a little. If its too clean you may lose throttle response. If its really chugging, it may stumble trying to get on the pipe.
- Location
- Riverside, CA
First off, looking at plug color is a waste of time! The reason spark plugs use to develope
color was because of the lead in the gasoline. But you are running unleaded, so the only
thing that adds color to the spark plug is your premix, and it is a poor substitute!
Your carb base gaskets and maybe your intake manifold gaskets are leaking. Did you
thoroughly clean your gasket surfaces and replace the gaskets??
Engines run away when the carb base gaskets are leaking. But, if your idle changes when
you raise or lower your handpole, the throttle cable is too tight. Also leaking intake manifold
and / or reed gaskets will contribute.
Your pop-off seems a bit low (to me) for a Yamaha. What brand were the carb parts?
But because you have primers, your SuperJet most likely had a hard starting problem
at one time. A lot of people also lower the pop-off to help a hard starting engine. It
is my experience that Yamaha's run, and start just fine with the hi stock pop-offs after
all the vacuum leaks are fixed.
I am also curious about the o-rings on the needle and seats.
With primers you should not have any problems starting. Even if you had the adjustment screws
to lean, it should still kick off. Are you opening the throttle while you are trying to start it??
Bill M.
You need to fix all of your vacuum leaks, and if you learn the idle drop test, you will know when
the starting, idling and low speed is rich or lean.
Is there any mods to your ski besides the carbs? Do you ride in Mission Bay or drive to the
river?
color was because of the lead in the gasoline. But you are running unleaded, so the only
thing that adds color to the spark plug is your premix, and it is a poor substitute!
Your carb base gaskets and maybe your intake manifold gaskets are leaking. Did you
thoroughly clean your gasket surfaces and replace the gaskets??
Engines run away when the carb base gaskets are leaking. But, if your idle changes when
you raise or lower your handpole, the throttle cable is too tight. Also leaking intake manifold
and / or reed gaskets will contribute.
Your pop-off seems a bit low (to me) for a Yamaha. What brand were the carb parts?
But because you have primers, your SuperJet most likely had a hard starting problem
at one time. A lot of people also lower the pop-off to help a hard starting engine. It
is my experience that Yamaha's run, and start just fine with the hi stock pop-offs after
all the vacuum leaks are fixed.
I am also curious about the o-rings on the needle and seats.
With primers you should not have any problems starting. Even if you had the adjustment screws
to lean, it should still kick off. Are you opening the throttle while you are trying to start it??
Bill M.
You need to fix all of your vacuum leaks, and if you learn the idle drop test, you will know when
the starting, idling and low speed is rich or lean.
Is there any mods to your ski besides the carbs? Do you ride in Mission Bay or drive to the
river?
Last edited:
- Location
- San Diego, California
i used makuni parts and got new needle and seets cause the old ones hadd a ridge in the tip of the needle. i used new gaskets how would i tell if theres a leak? everything got tightened down . the only way to get it started again is to open the throttle or it wont start, no mods to ski i mean engine wize. reeds are stock i checked them when i did the carbs and they look good. i rride in mission bay mostly. i only have problems starting after i ride it. if it has been sitting for a while it fires right up.
i think i might just pull the carbs and check everything all over again and go from there. it s not like i dont have enough extra gaskets to do it all over again. thanks for all the replys and help.
i think i might just pull the carbs and check everything all over again and go from there. it s not like i dont have enough extra gaskets to do it all over again. thanks for all the replys and help.
- Location
- Riverside, CA
Sorry for the long post, Comments are on the top, and action is in the second
half of the post.
I was a pro mechanic from 79' to 2005' and worked on primarily Kawasaki &
SeaDoo, but I worked at a few multi line dealers that sold Yamaha's too. So,
I am a little fuzzy on how Yamaha used their alpha numeric designations for
engines.
All the companies: Kawasaki, SeaDoo, Yamaha, Polaris, Tigershark, WetJet, and
the smaller companies that used parts manufactured by Performance Jet
Ski (Systems) all had the same carburetor problems.
I assume you have twin carb engine with dual 38's. Yamaha used an intake manifold
with a lot of gaskets. For example, it is possible you removed the carbs, but did
not separate the carbs from the mounting plates. The (2) carb base gaskets are a
common vacuum leak, but so is the other gaskets on the intake manifold.
On close inspection Yamaha had some of the worst machined parts of the
watercraft manufactures. They look like they had the cnc machines set for the
fastest feed possible. That resulted in gasket surfaces that only appear flat. The
machining on Mikuni base gasket surfaces were never very good either.
I asked about opening the throttle while starting because I thought you might
have more than one problem. It sounds like you are too rich, and you have
vacuum leaks that are causing the engine to run away. (look at steps 1 thru 4)
I mentioned what parts brand you purchased because of the possibility of the
needle and seats leaking at their o-rings during a pop-off test. The Mikuni kits
available on E-bay do not come with o-rings for the seats, and I do not trust
the needle and seats they sell either.
I mentioned Mission Bay vs Colorado River because riding at the river this time
of year needs at least 3 main jets sizes leaner than good jetting for Mission Bay.
This time of year in the desert, the air density is similar to a 5500' mountain lake.
Back in the mid-90's the performance difference between California and Arizona
was so noticeable, that Yamaha issued a technical service bulletin advising dealers
how to tune their customers waverunners for the Colorado River. But because you
ride at Mission Bay, lean running problems can be more noticeable.
Bill M.
Action:
You may want to plan on making your own gaskets with Felpro 1/16" & 1/32" rubberized
felt (from NAPA Auto Parts) and an X-Acto #2 knife. It is easier to make thick gaskets,
than it is to flat sand the gasket surfaces. But I can give instructions on building a
flat plate with sandpaper, that you can build from regular supplies from your local
hardware store.
(1) Remove your carbs (but do not disassemble them for now).
(2) Look at your gaskets as you are removing the carbs. If there are any signs of wet or
damp gaskets. You have found a vacuum leak.
(3) Remove the carb adapter plates, and inspect the carb base gaskets for wet or dampness.
(4) While the carbs are still assembled, do a pop-off test, and compare your earlier results.
If the needle and seats (N&S) pop-off with less pressure, or leak, that means your lever is adjusted
incorrectly and is a likely cause for the engine to require throttle while starting.
Pop-off testing: Test the pop-off twice for each carb. Once after the fuel pump, N&S, lever and
spring have been assembled. Second, verify the pop-off with the diaphragm and cover tightened
down.
I like testing the pop-off (when the diaphragm & cover is removed) using WD-40 and a 1 gallon
Zip-loc freezer bag. Put the carb inside the bag so you can watch it pop-off and not make a
mess.
(5) Remove the intake manifold and inspect the 2 gaskets and the reeds. Again, you are looking for
signs wet or damp gaskets.
(6) Use the 1/32" rubberized felt for the 2 gaskets between the intake manifold and the engine.
(7) Use the 1/16" rubberized felt for the 2 carb base gaskets, and for the long carb adapter
gasket.
(8) Learn how to power tune your ski on the boat ramp. Always begin with the pilot/low speed
circuits by adjusting it with the instructions in my blog on pwctoday for the idle drop test.
(in the jetting basics post)
Bill M.
Note: If you start the boat the before you fix it, leave the top of the flame arrestor off, and
keep a couple of spare rags or plastic bags that you can stuff into the top of the carbs and
starve the engine of air. That is a good way of stopping a run-away engine.
half of the post.
I was a pro mechanic from 79' to 2005' and worked on primarily Kawasaki &
SeaDoo, but I worked at a few multi line dealers that sold Yamaha's too. So,
I am a little fuzzy on how Yamaha used their alpha numeric designations for
engines.
All the companies: Kawasaki, SeaDoo, Yamaha, Polaris, Tigershark, WetJet, and
the smaller companies that used parts manufactured by Performance Jet
Ski (Systems) all had the same carburetor problems.
I assume you have twin carb engine with dual 38's. Yamaha used an intake manifold
with a lot of gaskets. For example, it is possible you removed the carbs, but did
not separate the carbs from the mounting plates. The (2) carb base gaskets are a
common vacuum leak, but so is the other gaskets on the intake manifold.
On close inspection Yamaha had some of the worst machined parts of the
watercraft manufactures. They look like they had the cnc machines set for the
fastest feed possible. That resulted in gasket surfaces that only appear flat. The
machining on Mikuni base gasket surfaces were never very good either.
I asked about opening the throttle while starting because I thought you might
have more than one problem. It sounds like you are too rich, and you have
vacuum leaks that are causing the engine to run away. (look at steps 1 thru 4)
I mentioned what parts brand you purchased because of the possibility of the
needle and seats leaking at their o-rings during a pop-off test. The Mikuni kits
available on E-bay do not come with o-rings for the seats, and I do not trust
the needle and seats they sell either.
I mentioned Mission Bay vs Colorado River because riding at the river this time
of year needs at least 3 main jets sizes leaner than good jetting for Mission Bay.
This time of year in the desert, the air density is similar to a 5500' mountain lake.
Back in the mid-90's the performance difference between California and Arizona
was so noticeable, that Yamaha issued a technical service bulletin advising dealers
how to tune their customers waverunners for the Colorado River. But because you
ride at Mission Bay, lean running problems can be more noticeable.
Bill M.
Action:
You may want to plan on making your own gaskets with Felpro 1/16" & 1/32" rubberized
felt (from NAPA Auto Parts) and an X-Acto #2 knife. It is easier to make thick gaskets,
than it is to flat sand the gasket surfaces. But I can give instructions on building a
flat plate with sandpaper, that you can build from regular supplies from your local
hardware store.
(1) Remove your carbs (but do not disassemble them for now).
(2) Look at your gaskets as you are removing the carbs. If there are any signs of wet or
damp gaskets. You have found a vacuum leak.
(3) Remove the carb adapter plates, and inspect the carb base gaskets for wet or dampness.
(4) While the carbs are still assembled, do a pop-off test, and compare your earlier results.
If the needle and seats (N&S) pop-off with less pressure, or leak, that means your lever is adjusted
incorrectly and is a likely cause for the engine to require throttle while starting.
Pop-off testing: Test the pop-off twice for each carb. Once after the fuel pump, N&S, lever and
spring have been assembled. Second, verify the pop-off with the diaphragm and cover tightened
down.
I like testing the pop-off (when the diaphragm & cover is removed) using WD-40 and a 1 gallon
Zip-loc freezer bag. Put the carb inside the bag so you can watch it pop-off and not make a
mess.
(5) Remove the intake manifold and inspect the 2 gaskets and the reeds. Again, you are looking for
signs wet or damp gaskets.
(6) Use the 1/32" rubberized felt for the 2 gaskets between the intake manifold and the engine.
(7) Use the 1/16" rubberized felt for the 2 carb base gaskets, and for the long carb adapter
gasket.
(8) Learn how to power tune your ski on the boat ramp. Always begin with the pilot/low speed
circuits by adjusting it with the instructions in my blog on pwctoday for the idle drop test.
(in the jetting basics post)
Bill M.
Note: If you start the boat the before you fix it, leave the top of the flame arrestor off, and
keep a couple of spare rags or plastic bags that you can stuff into the top of the carbs and
starve the engine of air. That is a good way of stopping a run-away engine.
Last edited:
- Location
- Charlotte, NC
if you have the stock flame arrestors with the stock popoff and no screens in the flame arrestors then you will definitely have a bog because your popoff is off with no screens in the flame arrestors. they came with three screens per carb stock. if you dont have any screens, then try a lighter spring on your needle and seat. i personally take 2 screens out but i also put a lighter spring to compensate. the stock is 115g, you could try a 95g spring or simply put all of the screens back in.
- Location
- Riverside, CA
Either you have an 80gr spring in your carbs, or your needle & seats are leaking.
Look at the Mikuni Spring ID & pop-off psi.
I have never changed the pop-off for new (or no) flame arrestors. It is simply not
needed. For that matter, neither is replacing the hard jets. I have charged people
for rejetting before, but most applications only require a change to the fuel screws.
Only the JS440/550/and early 650's had a restrictive F/A. Most of the Kawasaki's,
Yamaha, and SeaDoo's had free flowing F/A's. The only late model SeaDoo that
needed jetting was the 951.
Bill M.
- Location
- San Diego, California
i set thr pop off to 35 becuse of reading "Loads of wisdom located here: http://www.groupk.com/tec-carbs98.htm " where it says pop off should be no less than 25 and no more than 35 so i made a spring that gave me 35 . i have the 65 spring and the 119 spring still from the rebuild kit. but i think i found the cause of the leak on the carbs check out this picture i put the bolt back in so u can get the idea on whats happening when its all together 1st pic is where look at the three bolt holes the single hole by itself
and the second pic is the bolt in the hole showing what i think is happening
see the bolt going through and pressing on the back of the carb i think this is why it is random cause sometimes i had the top off and sometimes i had it on also i see round divits in the top that match the bolt going through and pushing on the top. so i doubbled up on washers on those two bolts. i did reconize the gasket on one side looked a little wet. im really intrested in those homemade gaskets where do u get the material to make them are they universal gasket materal>? the ruberized felt? i still want to retighting all the bolts on the carb and replace those gaskets. there is one gasket under the carbs then inbetween the reeds and the engine how many it looks like two or three from the owners manual but im not sure? thank you all who have helped and comented im trying to learn as much as i can and all the help is appreciated.
and the second pic is the bolt in the hole showing what i think is happening
see the bolt going through and pressing on the back of the carb i think this is why it is random cause sometimes i had the top off and sometimes i had it on also i see round divits in the top that match the bolt going through and pushing on the top. so i doubbled up on washers on those two bolts. i did reconize the gasket on one side looked a little wet. im really intrested in those homemade gaskets where do u get the material to make them are they universal gasket materal>? the ruberized felt? i still want to retighting all the bolts on the carb and replace those gaskets. there is one gasket under the carbs then inbetween the reeds and the engine how many it looks like two or three from the owners manual but im not sure? thank you all who have helped and comented im trying to learn as much as i can and all the help is appreciated.
- Location
- San Diego, California
i see u already told me where to get the gasket materal , i should read alittle closer before i ask questions thanks bill
- Location
- Riverside, CA
Klemm has a good writing style, and there is good info on his site.
But there is also some bad info, and some crazy back yard mechanic
theory in there as well.
The worst problem I have with his site, is the lack of effort to edit
the bad and crazy stuff out of the site.
I just reread some of Harry's pop-off information and I had a OMG!! moment.
IMO it is bad advice to recommend a drastic change in pop-off to non professional readers.
Generally speaking, it is not a good idea to cut or stretch springs.
There are no vacuum leaks above the venturi.
There should be a short bolt that hole.
Keep the nuts & bolts you remove in groups, and put them inside a cup cake
baking tray.
There is a small gasket under each carb (see attachment), and the carbs
are bolted to one long gasket. So, a total of 3 gaskets directly under the
carbs. Then there should be 2 gaskets between the manifold and reeds
with a thin plate in between.
I will try to post the part# for the gasket material.
Bill M.
Attachments
Last edited:
- Location
- Riverside, CA
Napa part #'s
1/16" FPG 3187 Rubber fiber gasket material (10" x 26")
1/32" FPG 3157 Rubber fiber gasket material (10" x 26")
Cut a bolt hole, insert a bolt, stretch out the gasket material and cut
another bolt hole. Cut as many bolt holes as possible before cutting
intake tract.
Get yourself an X-acto knife at a Hobby shop, Office supply, or Crafts
store. A #2 knife or equivalent works well. You will need extra
replacement blades.
Bill M.
1/16" FPG 3187 Rubber fiber gasket material (10" x 26")
1/32" FPG 3157 Rubber fiber gasket material (10" x 26")
Cut a bolt hole, insert a bolt, stretch out the gasket material and cut
another bolt hole. Cut as many bolt holes as possible before cutting
intake tract.
Get yourself an X-acto knife at a Hobby shop, Office supply, or Crafts
store. A #2 knife or equivalent works well. You will need extra
replacement blades.
Bill M.
Attachments
Last edited:
- Location
- San Diego, California
cool thanx i have xacto knife and a pack of blades that happen to be #2 , im going to pick up the gasket materal tomorrow. should i use the old gaskets as templits and trace on to the new materal then cut out?