1994 v150 running rough, please help !!!

[cbucner]

Hello!
I got this boat last year, and started working on it for this summer.
It's a 150 ser 0G028824 .
Up to now I put new plugs, new set of wires , new t-stats , took out the carbs and checked to see if there is any gunk or if they are dirty, they were clean used air pressure , blowed all jets and passages put new gaskets and put'em back.
The engine runs exactly the same as before I did all this, first time I started it.
I'm running from a gallon size can since I have to clean the tanks of the old gas.I'm running premix 50:1 to the fuel pump, removed the oil injector.
the engine idles ok but if you're trying to go higher in rpm's it goes rough.
sounds like it's missing on one or more cyl's .
I can't get it over 3k or it will fall apart, vibrates and sounds rough.
I installed a fuel pressure gauge in between the fuel pump and the first carb and I have about 4psi at idle and it goes up a bit when you give it some gas.
Never drops under 3 psi. I'm wondering if this a good pressure or not!!
I removed wire by wire at the plugs and they seem to fire all, I can notice the diference with the wire removed.
What's next.
I made a video with my cellphone with the engine running , I don't know if you maverick mechanics out there can figure out what's going on just by watching this video or listening to the engine.
Here's the link:

http://64.65.22.75/movies/nitro/v150.wmv

It's about 13mb. I will try to make a better one where you can hear the engine better.
Any input is appreciated.
Thanks

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

And also can anyone tell me what's up with this engine from the serial nr,
like exact model and where was made etc...
OG028824
Thanks

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

Forgot compression test was around 120-125 on all cyl's.

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

Here's the link for a second video taken at the prop , sounds better .

http://64.65.22.75/movies/nitro/v150partII.wmv


Thanks

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

update : did a spark test and all sparks fine at 5/16" gap.
I hooked up my timing light to see if the boat tach is good and it look like it's a bit high, idles at 850-900 and if I rev it up it looks like it's rough even up to 2k rpms.
if you keep the carbs open let's say at 2k the engine will go up and down in rpms and running bad.
any help appreciated.

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

anyone??

 

[j_martin]

Re: 1994 v150 running rough, please help !!!

What's all the smoke. If it's steam, you have a water intrusion problem.

Sounds like it's missing for whatever reason.

Anything over 1 lb of fuel is plenty on the muffs. 2-3 lbs will run it at WOT.

hope it helps
John

 

[BF]

Re: 1994 v150 running rough, please help !!!

any chance that either you, or the previous owner, mistakenly crossed a couple of the spark plug leads? (going to the wrong plugs)

My Dad did that on the I/O he used to have. He asked me to help him fine tune the carb... I didn't like how it sounded and after some digging, figured out he had mixed up 2 wires when he had replaced the wires the fall before. Oops. Ran WAY better after switching them back

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

That's how it smokes!!!
I'm running out of a premix can at 50:1 ratio.
89 gas + penzoil synt 2 cycle oil.
I have 2 jetskis and they smoke even worse so I was thinking it's normal!!!
I have to much smoke???
How do I do the idle mixture on the carbs on this motor .It's an XR6 just found out today.
Thanks
any common problems on these xr6's with ignition / spark ??

 

[cbucner]

Re: 1994 v150 running rough, please help !!!

I checked all the wires twice and they are all in the right place.
checked for spark and it's good , how can I use the timing light to figure out if one cyl it's firing more than once or is missfiring??
I tried something and it looks like no4 it's missing sometimes.
I used the timing light and the other cylinders give a steady image on the flywheel , no4 however sometimes doesn't line up in the same spot !!
Could this be the problem??
second I tried to remove one wire at the time and rev it up just a little to see if the engine will act the same and it looks like it doesn't matter if I pull any of the wires it will run the saem way so I'm thinking that it may be carb related like idle mixture.
I would really wanna do the mixture from scratch on these carbs.
how I have to ask you guys!!
Thanks