New Engine, Running Issues

brapperdoodle

brapperdoodle

Location
Asheville, NC
So i've been able to get some hours on my ski and have it tuned in pretty well! I'm really loving the new pump the most, Its really night and day hook up from my old stock (and probably worn out) pump. One thing i'm having trouble with is after I fall off the ski doing whatever, It bogs a bit and will not rev out for 5 seconds or so and then jumps back up and hits. Weird thing is, this ski used to do the same thing last year before I rebuilt everything. I suspect this to be water inside the hull, splashing into the intake. I'm running my stock Yamaha intake because I believe it is the best at keeping water out of my engine, it is facing the correct direction and shouldn't be part of the issue. While diagnosing the water inside my hull issue, I ran the ski on the hose for a minute and I found 2 leaking clamps and tightened them. I also found that my new Blowsion hood seal doesn't really seal all that well, with the hood on I sprayed around the sealing surface and found that the front leaks horribly. Does anyone have a suggestion on how to get a better seal? Maybe a new seal totally or just add some wide weatherstripping to the new seal that's in there? Anyways I want to believe this is where the water is coming from and will hopefully fix my bog issue.

Problem #2 While riding with @Sanoman and @hornedogg79 I got my jetting pretty close and really dialed it in a few days later. I ran a new set of plugs last time I went out and looked at them today, They looked great. Mocha colored all the way down the electrode and slightly wet. I know this is not a proper plug chop test, but after running a tank of gas through the ski I wanted to see what the plugs looked like. My issue is that the ski still acts a bit sluggish and has a hesitation down low, very slight but noticeable when you're try to get some pop off a wake. Also the ski won't idle, it always loads up and stalls and won't start without blipping the throttle. Its also a pain to start when its cold, the primer makes it start but it won't stay running for a bit unless you keep it running with the throttle. I have tied the ski to a dock and followed the proper procedures for adjusted the idle, low speed adjustment and FCV. Everything seems to be set correctly and the ski runs well when you're riding but doesn't like to idle for long. I noticed today that when I got the ski idling on its own, i turned the hose on and when the water got to the engine it didn't want to idle and the engine vibrated like crazy. @Sanoman has seen a video of the crazy engine shake, you'd swear something was fooo_Oked. Just wanting to get some input for where I should go next on trying to track down these issues. I also started to tune in my B-pipe but i'll get into that later, crazy how much difference the screws make and which ones you open and close...
 
Sanoman

Sanoman

AbouttoKrash
Location
NE Tenn
l’m not familiar with how the hood seals on a square.ls there anyway to install a Watcon seal on the side that doesn’t have one?
Had to do that on my predator,water was just pouring in the sides
 
mikidymac

mikidymac

Location
California
On my square the front seal groove was noticeable sagging like most squares do. What I did was get the ski level and mixed some epoxy up with some cabosil and chopped glass until it was stiff but would still flow and poured just enough into the seal groove and let it flow out to the sides to level it.

I then scuffed up the entire groove and installed a new Watcon seal and almost nothing is in the hull after a ride.
 
hornedogg79

hornedogg79

dodgin' bass boats
Sounds like you may have a little too much water spraying out of the top of your headpipe. That or a small leak in your exhaust or head gasket. It shouldn't change behavior like that when you add water to the mix. The hard starting and idle issue sounds like lack of fuel on the low side. Primer wouldn't help if it was already loaded up with fuel. Unless I do a long run wfo plug chop my plugs always look black and wet. Also carb setrings that work for skis at sea level may not be the best for you up in the mountains of southern Appalachia. I've had good luck with factory pipe's recommended jets 120L 140H, but the pop may need to be a bit lower. Try 15-20psi and see if it helps. You may lose some low end response but I would rather it start and idle easily.
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
hornedogg79 said:
Sounds like you may have a little too much water spraying out of the top of your headpipe. That or a small leak in your exhaust or head gasket. It shouldn't change behavior like that when you add water to the mix. The hard starting and idle issue sounds like lack of fuel on the low side. Primer wouldn't help if it was already loaded up with fuel. Unless I do a long run wfo plug chop my plugs always look black and wet. Also carb setrings that work for skis at sea level may not be the best for you up in the mountains of southern Appalachia. I've had good luck with factory pipe's recommended jets 120L 140H, but the pop may need to be a bit lower. Try 15-20psi and see if it helps. You may lose some low end response but I would rather it start and idle easily.
Click to expand...

I need to come back out and ride soon, or if you guys ever want to come visit Lake James!

Id like to try a different pop-off because mine is at about 30psi now. 120L and 145H I believe on a single Mikuni.

The ski runs acceptably, you've seen it but its still not quite right. While riding it last time I was able to fully close my lowest pipe screw and just leave the top at 1/4 open, so everything is closed except the top. The ski for sure ran differently but my pipe still wasn't getting hot enough to sizzle. By the time I closed the top screw enough to get the pipe to sizzle water right at the coupler, it ran horribly. It was about 1/8 turn open and the others closed. The ski had no power and would barely get onto the pipe. I opened it back to about 1/4 and it ran okay. I hope this is not contributing to my running problems but I have not confirmed that the lower screws are actually blocking all the water. I might need to pull the pipe and hook it to a hose and check the actual spray pattern...

Ive been reading this : http://www.x-h2o.com/index.php?thre...p-water-screw-for-best-spray-patterns.133660/

and this : https://en.m.wikipedia.org/wiki/Expansion_chamber

If anyone has any other good articles please share
 
550kid171

550kid171

Location
UT
I would also say try and drop the pop-off a few psi. When i was playing with jetting on a 61x with a b pipe I had a hard low-mid end stumble when blipping the throttle, it wouldn't start cold after a day or so without choking or priming it and it would never rev out clean on the trailer . I dropped pop-off about 10 psi and it tottaly cleared up all of my issues. I would say get the carb dialed in then work on the pipe tuning from my personal experience. Tuning both at once can cause some headache
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
I rode today and had a great time. I turned my idle up just a bit and it seemed to totally clear up the idle issue... not sure how I missed that but it idles much better now! Still have the cold starting issue and I believe it to also be related to pop off pressure. I have several springs that are labeled so I can try a few and see what gets me a lower PSI. Im still feeling poor throttle response in the low end and its very bothersome because the ski has a hard mid hit, so it will hit a little bit late and kinda messes with cornering. Im leaving the pipe screws where they are for now, just 1/4 open on top and ill mess with that later. I also noticed that while doing tail spins, the ski will load up and not come back on to the pipe trying to pull up out of it. It takes a second to clear up.

Also curious, im going to get the jetting straight first but like I was saying the ski has a hard mid hit and tons of pull up to top speed which is WAY faster than I want to go haha. How much does the pitch of the prop effect the power delivery? I would much prefer the hit to be at slower speed/lower rpm. I have to hit boat wake so fast I can't get much height but Im going pretty far on a good air. Just wondering if this is something to consider later. I was sold a Skat 10-16 prop for my Skat 144 set-back mag.
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
Finally had time and pulled my carb today, I had a few unmarked springs and a few new ones that were marked. I ended up using a 95gram spring, giving me a pop off of around 27psi. I noticed while testing the pop off springs that they never really pop. They just begin to hiss and allow air through the needle and seat. I had a brand new OEM Yamaha carb rebuild so I decided to replace the needle and seat and just go ahead and replace all the gaskets. I originally sent my carb to GroupK when having the engine work done, I thought they would rebuild the carb while doing whatever they do but apparently not. I found that the gasket for the fuel pulse diaphragm was missing! Not sure what I paid them to do to my carb but I'm sure it didn't involve losing gaskets... Who knows maybe it was missing before I sent it to them, but I had never opened that carb that was on my ski when I got it. Anyways, its in there now and I replaced the hi-low screws with the ones supplied in the kit. Im currently at 120L 145H and a 95gram pop off spring. When re-installed on the ski, it cranked and died, probably because of the lines priming but them started nicely and idled well. It seemed to have a noticeably more crisp throttle response just whapping it open off idle. Revved much cleaner. Im on the way to the lake first thing in the morning, hopefully that throttle response will be there in the water haha.
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
Ski ran pretty well today at the lake, defiantly has a more crisp throttle response off idle and at low RPM but it did take about 30 minutes of tuning to get it riding properly. Its much better than before, I still think it could be just a pinch better but I will have to keep tuning it and record my settings to get it just right. I also added a piece of nice automotive weatherstripping to the front seal of the hood, it seemed to help a good bit with water intrusion. Still needs to be sealed better but I think the added weatherstripping will be a good fix for the time being.

IMG_6781.jpg
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
I’ve got my ski running pretty well, but the only issues that remain are that the tailpipe is very black and is getting buildup under the bond rail and on the dash. The other issue is that the ski will start to bog a bit when doing tail spins... it clears up after leveling out the ski and riding away but has hardly any power to pull out of the tail spin and ride out. Otherwise the ski seems to run very well, starts great, restarts great, seems to be pretty close. Any ideas?

92C27B02-9896-4F0C-AAE2-D5E345B863AE.jpeg92FA7653-5569-4C87-84F8-2D6B42456923.jpeg
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
What oil are you using? Some oils are leave a fair amount of sludge. Some are cleaner. You may be a little on the rich side and passing some unburned fuel causing extra sludge (just my theory). When doing tail stalls the exhaust gets sucked into the pump causing cavitation. This is why many use to run a side exhaust also with the rear exhaust. This kept the exhaust from getting sucked into the pump.
 
wmazz

wmazz

Location
Riverside, CA
550kid171 said:
I would also say try and drop the pop-off a few psi. When i was playing with jetting on a 61x with a b pipe I had a hard low-mid end stumble when blipping the throttle, it wouldn't start cold after a day or so without choking or priming it and it would never rev out clean on the trailer . I dropped pop-off about 10 psi and it tottaly cleared up all of my issues.
Click to expand...

That is an indication that a problem exists (imagined or otherwise), the
so called problem wasn't fixed by lowering the pop-off.



Bill M.
 
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fastgtfairlane

fastgtfairlane

Location
Charlotte, NC
try opening your top screw on the head pipe 1/2 to 3/4 turn. that will help off idle acceleration. opening the top screw to 3/4 turn helped bottom end acceleration on my superjet quite a bit. im also running a dedicated cooling line to the pipe to keep the headpipe cooler. hell my x2 i have the top screw open 1.5 turns out and the middle 1/2 turn out. it made the acceleration smoother and more linear than peaky on top.
 
brapperdoodle

brapperdoodle

Location
Asheville, NC
Big Kahuna said:
What oil are you using? Some oils are leave a fair amount of sludge. Some are cleaner. You may be a little on the rich side and passing some unburned fuel causing extra sludge (just my theory). When doing tail stalls the exhaust gets sucked into the pump causing cavitation. This is why many use to run a side exhaust also with the rear exhaust. This kept the exhaust from getting sucked into the pump.
Click to expand...

Klotz Ski Craft, 40:1

I always go by the pump measurements at the gas station, but that never seems to line up with the actual fuel jug measurement. So if anything, it may be closer to 32:1 only because 5 gallons at the pump is like 4.5 according to the fuel jug...

Also that sounds legit about the cavitation but I think what I am feeling might be a fuel issue because the ski doesn't rev when opening the throttle, it takes a second to "clear out" if that makes sense. It doesn't choke or burble, just bowwwwahhhhhhAAAAHHHHHHHH!!! Not snappy like normal.. Again this is only during a tail spin and pulling out of one
 
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Harbor

Harbor

Location
Stockton
When I have my carbs setting too rich it leaves the black sludge like you have their... after tuning it in (leaning out) it goes away
 
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