ts monte carlo 770

[AC SHARKER]

I'm working on my 770 with dual Mikuni sbn 38's. Rebuilt carbs with a standard rebuild kit. Hasn't run right since. Can get to run decent but doesn't idle well consistently. When I do get it runnin good on top end, cuts out and loud roarin 2stroke sound turns to dull hollow type sound. Ski doesn't hardly die, just takes a minute or two and then everything is back to normal again , for a couple of minutes. Checked carb very good, all holes, orifices, etc. Didn't replace jets or needle/seat. I believe that this problem is somehow a lean condition based on plug readings. Very light brown to orange with no oily/goop around plug base. High speed adjuster doesn't seem to do anything. Also happens more frequently when in choppy water. Don't know if it's related. If anyone has suggestions or tips, let me know. Am checking pop off today. How often should jets, needle/seat be replaced? Mine look fine but what do you think?

[Technical Support]

Did you change your springs?

[AC SHARKER]

I did change the springs when I originally rebuilt the carbs. Now I think it's possible that the springs could have been wrong all this time. How or where can I find a pop off pump or suitable replacement around my area?

[Technical Support]

www.pro-tecperformance.com

[russthemuss]

maybe its cutting out on one cylinder? (dull hollow sound)Is it switching to limp home mode?(sits then back to normal etc )

[AC SHARKER]

It does do what your saying, I think I know where this is going. Overheat protection? I had the overheat/ half rpm limiter come on once before due to sand in my filter. It still runs loud and strong but only revs to 2500 to 3000 rpm. I can check the switch but am pretty sure it's some kind of carberator issue. It seems real lean on the rear cylinder which is fed by the secondary carb which is fed fuel from the primary carb. What is and what does the pulse hose do for the system? How does the fuel pump from the primary affect and relate to secondary carb?

[russthemuss]

Maybe its got a little water in the carbs? (hence the choppy water syndrome)I would pull them off and check them again.My 97 daytonas have a fixed high speed jet..are you sure your high speed jet is adjustable? (if this is what your calling high speed adjuster)
maybe the inline fuel filter is blocking up or the tank vent is blocked?

[AC SHARKER]

I did notice some small water beads when I opened the carbs up to check the pop off. I made a pump and checked my pop off, I had 30 psi when I should have 18. Replaced the springs, checked again, perfect. Did a few adjustments and went to the water.Runs great periodically. Idles good, no hesitation when I opened it up. When I let off of full throttle from a high speed run and let it return completely to idle speed, as soon as I grab the throttle to go, it goes back to that "dull hollw sound" for a minute or so then everything is normal. If I don't let it return copletely to idle speed before I get back on the throttle, it doesn't have any problems. I'm seeing alot of inconsistent situations. At full throttle for a couple of minutes it sometimes goes to that dull sound. Sometimes it doesn't. Sometimes while idling, even for a short period, it will get that dull hollow sound. I rode for about ten minutes at full throttle riding very wildly in circles hopping my own wakes, trying to see if it would cut out and it didn't. I then rode full throttle for a minute or so and it started to get that dull sound and I let off throttle a little and it stayed running good. I am really lost. I can correct what is the problem if I knew or could determine what the problem is. What is an anti-siphon valve? What does water do in the carbs and how does that affect engine or carb circuits? Is there a product anyone knows about that I can add to gas tank that treats moisture? There has always been a little water trapped in the bottom of the craft since I owned it due to poor hull drain design. These problems have only started occurring since my last carb rebuild. I have went over everything 2 or 3 times and don't seem to find anything wrong. I do have an adjustable high speed circuit via the high speed adjuster, the jet itself is fixed in carb. The adjuster is basically a neddle type valve. Any ideas anyone?

[AC SHARKER]

I really appreciate all the input from anyone that has posted. I have also learned quite a bit from other postings with similiar problems. This forum is excellent way for people to help others and also learn from other people's experiences. Thanks

[dank]

The water in the fuel system will get into the carb and clog the low speed jet. It will make it idle proley or not at all. When you do a high speed run and chop the throttle is should not die down like that unless the low speed adjusters are set to lean or the low speed jets are restricted. open the low speed adjusters 1/2 turn and see if it changes the symptom. It should not die when you chop the gas. You can go in from there until it stops hesitating from idle. If it is set to rich it will gerggle a little before it goes but shouldn't cut out. If it is cutting out then it is too lean. Hope this helps.

[AC SHARKER]

What is a possible way to identify fouled plugs? Can you notice when riding or only by looking? What is an anti-siphon valve and what does it do?

[Technical Support]

Anti-siphon valves are one way valves. Fouled plugs are black and usually wet - they aren't firing correctly. You can feel it from a misfire.

[AC SHARKER]

I have seen an article that says you can double up on anti-siohon valves. Is this true and if so, what negative effects can it have? I have been hesitant to richen the low speed up because I have been smelling alot of raw gas from the exhaust or at least that is what I think.

[Technical Support]

It's not needed on that ski the best of my knowledge. On a few skis it helps a low end over rich bog.