95 SL 750 Fuel vs Electrical Problem

[ron in kansas]

I have a 95 SL 750 and it’s killing me. I can’t get it to run right and I’ve tried everything I can think of. The motor blew two years ago and I had some guy in Indiana rebuild it and the carbs, now he won't call me back. (Performance Motor sports. Ft Wayne, Indiana.) I went to Iraq and now I’m back. I replaced the fuel sending unit float, the impulse line, put on a triple fuel pump, new plugs and filters, pulled off the carbs and found no dirt or clogs, reset the idle and high speed screws according to the manual. My problem is that it starts right up but as soon as you try to accelerate it bogs down. If you pull the choke very slightly it will get up on plane then if you hit a bump it sounds like all three cylinders start to work (jump in power) but only for a second until you hit another wave then it will do it again. I pulled the black box apart and found a loose wire, fixed that but still have the same problem. Could it be the CDI box? Plug wires, What am I missing?
Thanks for any help at all.
Ron

[mike741100xrp]

Re: 95 SL 750 Fuel vs Electrical Problem

sounds like carb problems but do you get fire to all three plugs also where the carbs rebuilt or cleaned I wuold start by rebuilding the carbs. with good kits and setting the pop off to the factory specs.
THANKS FOR YOUR SERVICE IN IRAQ U.S.A. MIKE

[ron in kansas]

Re: 95 SL 750 Fuel vs Electrical Problem

They were rebuilt, I just took off the diaphram and jets to make sure they weren't plugged, the plastic part on the under side is still there and I did'nt mess with it. I'm nervous about checking spark, due to the book saying the CDI will burn out if the plugs not properly connected

[ericfox]

Re: 95 SL 750 Fuel vs Electrical Problem

if you pull your choke out and that gives it more power> chances are you are running lean. Mine was doing the same thing after a carb rebuild. Try turning the low spead screws out 1/4 turn each to see if that fixes it. If that doesnt then turn each out 1/4 again until it resolves the problem. Also, have you ever replaced the fuel pump? might want to consider getting a triple outlet from mikuni. U can get one for about 30 bucks from denniskirk.com think they may be under snowmobile fuel pumps. its the only triple outlet pump on their site i believe.

[addicted]

Re: 95 SL 750 Fuel vs Electrical Problem

I had a nearly identical problem and it turned out the popoff was set too high. Like 23psi. i dropped to 15psi and it runs like a champ.

[scottso]

Re: 95 SL 750 Fuel vs Electrical Problem

I have also read issues about possible collapsed fuel lines. If fuel is suspect - that is another thing to check/replace. FYI - you apparently can't "see" a collapsed line by outside inspection - it collapses internally.

[johnsonmtz]

Re: 95 SL 750 Fuel vs Electrical Problem

I agree with Scottso, take a look at your fuel lines. If you have the original lines it's probably time to replace them anyway. Before I put my engine back in I replaced all of mine. I didn't find any that were collapsed but there were many soft spots. I went to my local CarQuest store and got 1/4" fuel line for $0.84 per foot. It's a cheap fix and will help rule out that problem and avoid future ones.

KJ

[scottso]

Re: 95 SL 750 Fuel vs Electrical Problem

By the way - I agree with mike741100xrp - THANK YOU FOR YOUR SERVICE IN IRAQ!

I thought "Performance Motor Sports" sounded familiar - check this

http://www.sbtontheweb.com/forum/sho...hlight=indiana

[ron in kansas]

Re: 95 SL 750 Fuel vs Electrical Problem

Thanks for all the ideas and the Support for our Troops, It's not my war I just protect my soldiers. (25 years and retire next June)

I'm not sure how to do the pop off test or adjust it. I have a new triple pump and will go get the fuel line tomorrow. Should I get the clear or does it matter if you can see through it?

[scottso]

Re: 95 SL 750 Fuel vs Electrical Problem

Clear is pretty. But I don't stare lovingly at my motor - I would just go with quality standard fuel line.

[ericfox]

Re: 95 SL 750 Fuel vs Electrical Problem

i heard the clear line is junk. I was told to go with regular black fuel line you can get at the auto parts store.

[tom21]

Re: 95 SL 750 Fuel vs Electrical Problem

maybe home depot clear hose is crap but I get the riva stuff and at least you can see the fuel in it. I would say my experience is that the needle and seat need to be replaced. You can check them with a popoff gauge. got that from riva too. most hard starting, no accel or low power ends up that they leak a little instead of holding til they pop. usually like 16.00 a piece.

[ericfox]

Re: 95 SL 750 Fuel vs Electrical Problem

you can also make your own popoff gauge.... go to store like grainger (big wholesale co. look up online to see if there is one near you) and get a pressure gauge about 0-30psi. you need small one so you can see small incraments. They should have a tee that can fit it too. you will need a little barbed hose fitting to go on each side as well. Then hook up one side to carb and block off other holes, and hook up the other side to aircompressor, bike pump, hand pump, or whatever and pump. watch the gauge and when it pops you should then know what psi it popped at. Mine cost prob 8 bucks to make. If you can find the tool the last guy was talking about... great.... if you cant then make one or you will pay 40-60 bucks buying one from a company like mikuni. Lata

[ron in kansas]

Re: 95 SL 750 Fuel vs Electrical Problem

ok, new fuel lines and I put the restrictor back in, reset the screws and opened the black box, one of the yellow wires was on the red bridge, That's why the RPM didn't work.the guage worked great but the engine is still doing the same thing. only now the guage quit working after about 10 minutes of riding around at idle to half throttle. It still won't take off like it did before the engine rebuild. only half throttle then it either dies or i manage to let off the gas in time and it drops back in the water on idle. choke doesn't seem to help like it did before. Any ideas on how to check crank seal leakage or any ideas at all?:emoticonn I've had this thing for two years and only got to ride it about 6hours when it actually preformed like it should. I am to the point that I either need to throw it away or drive 4 hours to the nearest mechanic( $46.00 hr to diagnose then, ? hours to fix. I've already got about $3200.00 into it.:emoticonr ) My wife is getting pretty sick :emoticonb of the whole thing and I don't give up on anything. HELP PLEASE>>>>

[Frisbee]

Re: 95 SL 750 Fuel vs Electrical Problem

without a pop off gage you are only guessing. each carb needs to hold about 15 lbs. pop off should be around 18 lbs. each carb. spray them with wd-40. it will give you more accurate readings. make sure your needle and seats are 2.0 in size. if 1.5 your pop off will be high. if wrong springs your pop off will be off. make sure you check and adjust your control arms. look through your jets make sure they are open.make sure your carb filters are clean. you will have to dissasemble the back sides of the carbs to get to them. resync your carbs when done and recheck to make sure they still hold pressure before you put the fuel lines back on. check your reeds also. this is an old boat ,you need to double check for correct parts,adjustments, etc. never know who worked on it last. good luck. i also suggest airbox upgrade with larger mains.