1994 GTX starting issues

[bevmale]

Hello members,
My ol' 94 GTX ran great last summer after top end rebuild. I have been starting a couple times per month since then. Ski is stored in garage. I've been having to choke to start just about every time. Yesterday it didn't cooperate. Compression a solid 150 both cylinders and nice spark as well. It did tease a few times as I was choking. Started to fire. As soon as I release choke and throttle up, just bogged down and dies. No acceleration like it is starving for fuel. The carbs were rebuilt approximately two years ago. After I completed top end rebuild, I did adjust carb settings to, what I hope, are factory specs. Also, I don't see any Fuel/oil mist shooting out of head when I crank without plugs. Is there an easy way to determine fuel delivery? Should I attempt to adjust settings again?

Thanks in advance for any advice..

 

[bevmale]

A bit of an update..Added a few drops premix to carbs instead of cylinders. It fired up. When I throttle up, it revs a couple times and it dies about the third or forth throttle up. Seems to be idling high when it does fire up. Any help greatly appreciated..

 

[Grim]

I would check to make sure you are getting fuel to the carbs. You can take off the main gas line from the fuel selector valve, omit the filter and put it in some gas and see if it picks up fuel, that will isolate if it is your filter, siphon tube or selector valve. Then work your way back if it is getting gas. if it is not getting gas you know its the carbs. Just my 2 cents
let us know how it goes.

 

[bevmale]

Thank you Grim,
I will do as described. When you say "omit the filter" are you referring to bypassing filter? Do I need to remove any lines from filter? I did notice after cleaning and replacing filter and housing and cranking a few times, plastic canister and filter completely bone dry. My apologies. The fuel system/carbs is new to me. Just very frustrated due to zero issues after I rebuilt top end and carbs rebuilt by pro shop prior and now start/fuel issues. I guess it's all part of the ol' 2 stroke ownership.
Thanks

 

[Grim]

Thank you Grim,
I will do as described. When you say "omit the filter" are you referring to bypassing filter? Do I need to remove any lines from filter? I did notice after cleaning and replacing filter and housing and cranking a few times, plastic canister and filter completely bone dry. My apologies. The fuel system/carbs is new to me. Just very frustrated due to zero issues after I rebuilt top end and carbs rebuilt by pro shop prior and now start/fuel issues. I guess it's all part of the ol' 2 stroke ownership.
Thanks

Yes, don't use a filter for this test. The idea is to have nothing between the gas and carb, that way you know if the carbs are the issue. If things work then it has to be between from the hose and the gas tank.... isolate components from there to figure out the clogger.

 

[bevmale]

Thanks again Grim,
Just to confirm. Remove fuel line that travels to carbs from selector valve..Place in premix and crank. If carbs pick up fuel and engine fires, problem/clog is selector valve or siphon tube. Assuming may be a good idea to remove and inspect fuel line as well to confirm it's not gummed up. I plan to replace gray lines soon. Is there a post that shows fuel system schematic?

 

[Babydriver]

Thanks again Grim,
Just to confirm. Remove fuel line that travels to carbs from selector valve..Place in premix and crank. If carbs pick up fuel and engine fires, problem/clog is selector valve or siphon tube. Assuming may be a good idea to remove and inspect fuel line as well to confirm it's not gummed up. I plan to replace gray lines soon. Is there a post that shows fuel system schematic?

Hey there...yea a guy on you tube shows you how to do it....step by step. 1/4 fuel line

 

[Babydriver]

Hey there...yea a guy on you tube shows you how to do it....step by step. 1/4 fuel line

Well that's what is on my 2 stroke...97 gtx 787

 

[TheGTIjetguy]

Thanks again Grim,
Just to confirm. Remove fuel line that travels to carbs from selector valve..Place in premix and crank. If carbs pick up fuel and engine fires, problem/clog is selector valve or siphon tube. Assuming may be a good idea to remove and inspect fuel line as well to confirm it's not gummed up. I plan to replace gray lines soon. Is there a post that shows fuel system schematic?

I took your post to mean you are still running gray “tempo” fuel lines? If so, that is most likely your problem. Replace all them with good line. I like the 25 foot black spool from Amazon. A good deal in bulk and it doesn’t harden when exposed to ethanol fuel. There are small screens inside the carbs that clog up with green goo from the gray lines and cause the symptoms you are experiencing.

 

[bevmale]

I took your post to mean you are still running gray “tempo” fuel lines? If so, that is most likely your problem. Replace all them with good line. I like the 25 foot black spool from Amazon. A good deal in bulk and it doesn’t harden when exposed to ethanol fuel. There are small screens inside the carbs that clog up with green goo from the gray lines and cause the symptoms you are experiencing.

Yes..Still running gray lines. Plan to change soon..
Thank you

 

[bevmale]

Just an update. I removed main gas line from the fuel selector valve. Placed line in premix and it appears carbs not picking up fuel. I removed and inspected fuel pump assembly off carbs. Seems to be ok, however, I did notice that all four screws were a bit loose. I reassembled and tightened as tight as possible. Unfortunately, the heads on all four screws are a bit stripped. Any resources for replacement screws and replacement fuel pump ? Assuming I should replace and tighten as much as possible before pressure testing. Also, any recommendations regarding fuel pressure test kit?
Thank you

 

[mikidymac]

You really should do a full carb rebuild using genuine Mikuni parts. You can get complete kits with new Alan head screws from OSD Seadoo parts.

You can’t check fuel pressure on these because they don’t actually burn pressure.

 

[bevmale]

Thanks mikidymac.. Just trying to do all possible without having to remove intake/carbs The carbs where rebuilt 3years ago by a very reputable shop, however, who knows what they used. I failed to mention. I did pour premix in carbs and it did fire and bog down as I tried to throttle. Is there a way to test pulse pressure? The pulse line is clear and when I put my thumb over, I can feel pulsing. Just not sure if enough pressure. Could the issue be related to failing crank seals or is that unlikely? Is there a way to rule that out? Just extremely frustrated because it ran great all last summer..

 

[bevmale]

Ordering genuine Mikuni carb rebuild kit. In the meantime, I removed fuel pump and valves, diaphragms, etc. seem to be ok. I can visually see the clear diaphragm pulsing while off as I crank engine. The black damper diaphragm looked a bit flimsy and stretched. No rips or holes. I reassembled and still not drawing fuel. As I crank, I just see teaser bubbles in my fuel container like its trying but no draw. Just to clarify. Main gas line placed in fuel direct to carb intake.. Is there a way to determine sufficient pulse more accurately vs. balloon test?

 

[mikidymac]

Pulse should be fine 99.999999% of the time it's the carbs.

 

[bevmale]

Thank you mikidymac. I can sleep a bit better now..