Low compression on all 3 cylinders
- Thread starter mkozak7
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Greg Moore
Member
You may have scored the cylinders but rare to do 3 at once, even rarer to do all 3 evenly. Nealy out of the question is head gasket, again too even. Most common cause by miles for evenly very low compression is timing slipped. If warranty, new engine for sure. If your $ paying, have the valve timing checked first, it isn't hard on these things, few things to pull then insert the crank lock followed by the cam lock. If cam lock won't go in, it's out of time. You pull the tensioner, then pull off cam gear. Then with cam now locked alter teeth/gear/chain until right marks visible away you go. There is no fine adjustment a tight chain needs to allow both the crank and cam locks to be in place, if they are, cam timing is dead on, if they can't both be placed cam timing is off
Thanks for the feed back. Although I already had the dealer replace the motor ($3,500.00 later). I wish I would have known about asking for them to check timing. I'm pretty sure they just wanted to get my money. I will ask them if they did that when I pick up ski. I am getting old motor back so I might just check for myself. The bad thing is that I have another 2011 RXTX as 260 that I am having lose of power and low rpm on. I am reluctant to take it to them.
when running on trailer i can give it throttle and it hesitates to get up to rev limiter. once it gets there i let off throttle a little bit and it gets right back to it fast. I can keep giving it throttle and it will maintain good response and hit limiter. if i let it go back to idle it hesitates to get back to limit.
intercooler is good no water coming out
Greg Moore
Member
If it's 2010 up with i-control throttle, they need to be tested for the rev thing on the hose. They won't go full throttle instantly until A, it's warmed up a bit and B it isn't in touring or eco mode..
it hits rev limiter on hose within 30 seconds of running. But it hesitates to get up to rpm once it gets there i can let off throttle for a second and get right back up to limit. But if i let it idle for about 10 seconds it hesitates again.
Greg Moore
Member
That has to be an IC thing, just tried my 10 215-iS and it's the same. Cable pulled throttle bodies for sure don't do this.
IC is good no leaks
Greg Moore
Member
Sorry not what I meant. Ic on these boats is intelligent control, aka fly by wire throttle.
On water it only reaches 6000 rpm and 52 mpg
benjilafouine
Well-Known Member
You mean 52 mph? at 52 mph from experience it is a little low for this ski (should be more like 65) but I doubt you would reach that speed at compression 60 psi. At 60 psi I doubt you would barely make it out of the trailer. It would die in the water.
Something is not adding up although I am not in any way a mechanics. From who did you get that 60 psi reading from?
Something is not adding up although I am not in any way a mechanics. From who did you get that 60 psi reading from?
benjilafouine
Well-Known Member
At 112-115, there is definitely a problem somewhere. That would explain lack of power such as hesitation, lack of power and lack of speed. How many hours are on this ski??? Some people says that 4-tec engines should last about 600 hours.
only 146 hrs on it. The intake preasure is 14.1 before start. I think it is to be around 14.7?? Could it be throttle body????
greenhornet2
Active Member
what's the spec on the compression? 115 might be too low and would cause a lack of power not letting the engine hit the max rpm to hit 65mph due to the load of trying to push more water and the PWC faster through the water, without the power it will never hit max speed. Without a load on the engine like running it on a trailer it doesn't need all of its horsepower to hit the rev limiter. If you lost 30% of your compression that's a heavy hit to your output power.
benjilafouine
Well-Known Member
Checking the compression does not have anything to do with the throttle because the engine is not even turned on when testing.
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