bigbaldbob
New Member
Very detailed post my friend.
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1996 GSX hard starting after carb rebuild.
- Thread starter cmeseadoin
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cmeseadoin
New Member
Hey guys, thanks for all the kind words and follow ups....I am just short on time beyond belief this week as I was at the lake all weekend and back to work for a couple days then back to the lake tomorrow after work...busy busy.
Here is the skinny from my last posting where I set my pop off pressures to around 35psi-ish from what I recall.......Well, I thought that was going to fix the issue and it did, NO more hard starting BUT....what had happened was that at 35-36psi pop off, I was then starving the engine for fuel under load. I got out there, engine fired first every time. BUT, under throttle, I would bog and not be getting enough fuel. SO, man was I pissed off.......I had to drag the ski home and tear out the carbs for what was going to be the LAST time. I now knew exactly what was going on. I reset my pop offs on BOTH carbs to exactly 23psi each...the lowest of the low spec...and it is now absolutely perfect. It fires up like it used to.....now if it does sit for 10 min or so, I do hold the throttle about 1/4 open and crank and it has to spin over a couple times before it catches, but it is basically immediate compared to what it was. This is how it used to be and it bothers me none. I have plenty of fuel on acceleration and wide open, engine runs great. If you let it only sit for a couple minutes, you can stab the button and she fires immediately and rests at idle like it should.
SO guys, the key it seems with this engine is to make SURE that both pivot arms in each carb are flush EXACTLY with the surrounding carb bodies AND set your pop off pressures NOT on the high end, more on the low end of the spec range and you will be fine. This was a learning process for me and the sad thing is it is simple to adjust, but pulling the ski home and out of the water, tearing out the carbs and adjusting, reinstalling and going back to the water is a PAIN IN THE ARSE! I did it 3-4 times to get it right where it should be.
Here is another neat little thing you can do so that you have some adjustment ability while you are on the water. As we all know that have the 787, the air box makes it IMPOSSIBLE to get to any of the screws on the carbs while the air box is bolted in the ski. If you are floating on the lake and want to tweak low speed or idle, GOOOOD luck.....So, I took some very flexible vacuum tubing with a small inside diameter and stuck it over the head of all the screws (low speed and idle) such that I could reach it while on the boat in the water. This was very helpful when I got back on the water because my idle was a little too low (1K rpm) when I put her back on the water and it was barely ticking over while the impeller was loaded in the water. I just popped the seat back and reached down there and turned my vacuum tubing. It's a great way to make little adjustments to the carbs because these ones are so hidden with the airbox. Low speed does not require much adjustment long as you are set within spec. This vacuum tubing is great for idle speed screw.
On my way to the lake tomorrow, I am looking at a 1997 GSX with the 787 and it has 130 hours on it. According to the owner, it is pristine and immaculate, zero sun exposure damage and just in top notch shape. (we all know how that goes..can't wait to see how it compares to mine, LOL) He want 2,500 and I might pick it up if everything passes my test and we work a deal. I have a 1996 and it's been a fantastic machine.....as of this weekend and with it finally running like new again, I got it to the lake house and it's 160 miles from my house on it's lift and covered and tarped.....this 1997 would be the "at home ski" for the river here. For 2500, what do you all think?
I hope I answered everyone's questions that were interested because you have similar issues. I'll be back next week....
:cheers::hurray:
Here is the skinny from my last posting where I set my pop off pressures to around 35psi-ish from what I recall.......Well, I thought that was going to fix the issue and it did, NO more hard starting BUT....what had happened was that at 35-36psi pop off, I was then starving the engine for fuel under load. I got out there, engine fired first every time. BUT, under throttle, I would bog and not be getting enough fuel. SO, man was I pissed off.......I had to drag the ski home and tear out the carbs for what was going to be the LAST time. I now knew exactly what was going on. I reset my pop offs on BOTH carbs to exactly 23psi each...the lowest of the low spec...and it is now absolutely perfect. It fires up like it used to.....now if it does sit for 10 min or so, I do hold the throttle about 1/4 open and crank and it has to spin over a couple times before it catches, but it is basically immediate compared to what it was. This is how it used to be and it bothers me none. I have plenty of fuel on acceleration and wide open, engine runs great. If you let it only sit for a couple minutes, you can stab the button and she fires immediately and rests at idle like it should.
SO guys, the key it seems with this engine is to make SURE that both pivot arms in each carb are flush EXACTLY with the surrounding carb bodies AND set your pop off pressures NOT on the high end, more on the low end of the spec range and you will be fine. This was a learning process for me and the sad thing is it is simple to adjust, but pulling the ski home and out of the water, tearing out the carbs and adjusting, reinstalling and going back to the water is a PAIN IN THE ARSE! I did it 3-4 times to get it right where it should be.
Here is another neat little thing you can do so that you have some adjustment ability while you are on the water. As we all know that have the 787, the air box makes it IMPOSSIBLE to get to any of the screws on the carbs while the air box is bolted in the ski. If you are floating on the lake and want to tweak low speed or idle, GOOOOD luck.....So, I took some very flexible vacuum tubing with a small inside diameter and stuck it over the head of all the screws (low speed and idle) such that I could reach it while on the boat in the water. This was very helpful when I got back on the water because my idle was a little too low (1K rpm) when I put her back on the water and it was barely ticking over while the impeller was loaded in the water. I just popped the seat back and reached down there and turned my vacuum tubing. It's a great way to make little adjustments to the carbs because these ones are so hidden with the airbox. Low speed does not require much adjustment long as you are set within spec. This vacuum tubing is great for idle speed screw.
On my way to the lake tomorrow, I am looking at a 1997 GSX with the 787 and it has 130 hours on it. According to the owner, it is pristine and immaculate, zero sun exposure damage and just in top notch shape. (we all know how that goes..can't wait to see how it compares to mine, LOL) He want 2,500 and I might pick it up if everything passes my test and we work a deal. I have a 1996 and it's been a fantastic machine.....as of this weekend and with it finally running like new again, I got it to the lake house and it's 160 miles from my house on it's lift and covered and tarped.....this 1997 would be the "at home ski" for the river here. For 2500, what do you all think?
I hope I answered everyone's questions that were interested because you have similar issues. I'll be back next week....
:cheers::hurray:cmeseadoin
New Member
I never did use the new diaphragms actually....I got so tired of fiddling and my originals were in such good shape and not leaking, that I got it running great again with the old ones and I have left well enough alone. I have the new ones should I ever need them. (PS...I'm looking at a 1997 GSX tomorrow that I might buy...so might be fiddling with mikunis again, LOL). I looked at them and mine look the same to me, the new ones just are obviously less tight than the old....but the old seem to work fine. At least now, I am MUCH more confident of how to set up these carbs that if and when I do this again on another engine, I will know more about HOW to do it. I went through what I thought was hell on this, but I learned A LOT.
Honestly, after looking at all of this, I think my flooding issue was not anything to do with pop off pressure....it was diaphragm related. The pivot arms were bent not to be flush and the diaphragm thing was pressing it and opening the needle and seat all the time. I rode it for an hour and lost close to half a tank of gas LOL! If the pop off is set too high, you are going to idle fine but you will have NO throttle, it will bog and stall out because it cannot get fuel. If pop off is too low, it will / can cause some hard starting, but not to the point of that needle and seat being held wide open by the diaphragm all the time. I have my pop off pressures now at the lowest of the low spec and she is not flooding at all when I stop the engine. Before, it was sitting there filling up with fuel and I was effectively cranking for several minutes trying to get it going. I thought I was going to get stranded and lose the battery or the starter LOL.
If you have massive flooding while sitting, check your pivot arm for the correct bend and make SURE your needle is not open in the seat all the time. (this is leak down and can be done by doing a pop off test with the carb together....if you lose all positive pressure with the carb together, your needle and seat are holding no pressure which means constant fuel supply.) Then make sure you have correct pop off pressures as well.
cmeseadoin
New Member
Who would do that? What a, pardon me, idiot. I could foresee some engine damage from doing this? Used engine oil? LOL, 4-stroke auto engine oil is not formulated to fulfill the requirements of these high performance, high compression, high horsepower-to-cubic centimeter 2-stroke engines. I hope your engine is ok.....make sure to run a compression test on each cylinder and also flush all oil lines, tank, etc really well and treat her right. :hat:
Def. make a pop off tester and set those carbs up right and I think you will find that the adjustments that you make internal to the carbs will solve your flooding issues. :hurray::cheers:
cmeseadoin
New Member
So I got up to the lake on Thursday afternoon and met the guy selling the red 1997 Seadoo GSX. It was a VERY nice and clean example of the boat, he knew the history and had all the service records....took it out and ran like new, perfect compression, etc. So, I bought it. I think I got a great ski for 2,500. 130 hours. Very pleased, now I have two of the GSX's. Here is a pic.
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