701 61x full throttle bogging

[MattyIce26]

I recently dropped in a 701 61x into my SN, and the first couple of times out this year it ran great. I transferred over my stock carb from my 650 but switch the jets for the 701. two weekends ago the ski started to bog out and not hit full throttle. Did a spark test and everything seemed ok. Took it out last weekend (Friday) and it ran great after I adjusted the carb back to stock 701 settings But the problem came back after I filled it with new gas on my last run and then....BAM no top end again! The ski just bogs and doesn't want to hit top speed like its choking.

I read some threads saying this could be a stator issue or electrical issue?? I don't have much experience with that. My e-box is out of the same sit-down as a the engine. Any input would be great. Thanks

 

[Quinc]

Check your fuel pick ups in your tank. Sounds like one is cracked and when you go full throttle it is not supplying enough fuel. If you still have the fuel selector switch I would get rid of it and run your fuel line from your reserve straight to the carb, and the On fuel line to your return.

Edit: you might also try running it in the water tied to a trailer with the hood off and see if you have an exhaust leak.

 

[DAG]

Your internal carb filter is
Clogged

 

[MattyIce26]

I'm already running a straight line from the tank to my carb, it doesn't pass through the selector. DAG could you explain what an internal carb filter is? Is that in the fuel pump? Thanks I'm a new to Yamahas

 

[eastcoastjumper]

take off the 4 screws on the fuel pump side of the cab. carefully separate the middle piece from the carb body and dont rip the small gasket in between. There will be a small black circle filter in there.

After you check that, turn your high side fuel screw out, ( counter clockwise) a little at a time. meaning 1/8th of a full turn out at a time. You are probably in need of some more fuel on the top end.

 

[MattyIce26]

So I've ridden the ski a total of 2 times since and I'm still having the same problem. I check the fuel filter, jets, needles. Everything looked clean. I took it out last Saturday tweaked both the high and low end screws with no prevail. A buddy of mine says it may be electrical? as if it's miss firing when I hit top end? It's so weird that it idles and runs at half throttle fine, once you give it everything it just bogs and does hit the high RPMs. Thanks anyway I appreciate the help as always.

 

[wanderer1]

Overheat sensor still attached? Could be malfunctioning and putting ignition in "limp" mode.

 

[MattyIce26]

Overheat sensor still attached? Could be malfunctioning and putting ignition in "limp" mode.

Well there's a new idea! Could you explain where this sensor is Wanderer1? I will check it out Thanks

 

[MattyIce26]

From researching it sounds like my ski maybe in "limp mode" The engine I bought its out of a Waverunner III. I'm confused about the pisser set up. The only cooling line I have is running from the back right section from the pump to the bottom of the exhaust port. Is that the only line I need or do I need to hook up a pisser line?

 

[Quinc]

Can you put your hand on the pipe and head? If you splash water on there does it steam off or sizzle right away?

 

[Magnum Mike]

I'm confused about the pisser set up. The only cooling line I have is running from the back right section from the pump to the bottom of the exhaust port. Is that the only line I need or do I need to hook up a pisser line?

Sorry if this sounds silly but do you have a pisser/pissers that let the hot water out off the head and dump overboard? The line from the pump is an cooling input, describe the routing of how water is leaving your engine.

 

[MattyIce26]

Sorry if this sounds silly but do you have a pisser/pissers that let the hot water out off the head and dump overboard? The line from the pump is an cooling input, describe the routing of how water is leaving your engine.

Nope you're not the silly one I think I am lol. Ok so the on my original 650 engine there was a line that ran between the head and the exhaust but it was split through a T fitting which exited through a pisser. However when I bought this 701, there was no T fitting, but simply a straight line that ran between the head and exhaust (Second picture) I may have overlooked connecting the pisser lol because I thought the setup on the 650 was after market. So in the first picture I put the T fitting back on and reconnected it to the pisser, does it look like that is correct now?

 

[Magnum Mike]

sorry, I was forgetting everything about stock cooling, but read this thread

http://www.x-h2o.com/index.php?threads/stock-701-exhaust-plumbing-question.137552/

I think you are on the right track if the pisser was not connected and now it is, even if this isn't the cause of your performance issue.

 

[NVJAY775]

Also a slim chance it might be your fuel tank check valve. Looks like an opaque white fuel filter coming out if your fuel tank. It is a one way valve to allow air in your tank as fuel is being used. But won't let fuel out. If it failed, your ski will lean out just like DAG said about the internal carb filter. Same symptom and very common failure.

 

[MattyIce26]

Ok so I took SJ out this weekend with the new pisser line installed. On the first run when I launched it, it ran great! Pisser line worked and rpms hit high end. Then after like 15 minutes it started to go back into limp mode... The water coming out of the pisser was very hot, but not so hot where it was burning my skin. I feel like it has to be overheating still? I check that fuel tank check valve and it seems to be working. I'm bummed out haha thanks again for the help. Not sure where to go now.

 

[MattyIce26]

Update: Unconnected the overheat sensor, looked like there was some dirt and crap inside and on the terminal that may have caused a bad connection. I ran it on the hose without the sensor on and it still was bogging. Next I took out the fuel filter (internal carb filter) and it looked like there was some "lint-like material" and gunk in that tiny screen. After I reassembled the carb it seemed to be running a little better. I think it's time for a carb tuning next. Fingers crossed boys!

 

[MattyIce26]

Just tuned the carbs. I believe I am running about 2-3/8 turns bottom end and 1- 5/8s. The ski screamed at the high rpms finally! I reconnected the overheat sensor as well considering that wasn't the problem. I'm gonna test it out on the water this weekend.

 

[wanderer1]

Glad its running better for ya. That many turns out on your adjustment screws I think you may want to consider jetting up.

 

[Sparkplug]

When the heat sensor trips, you will know. It wouldn't go more than 5 mph

Your screws are way too far out to be correct. Something is amiss somewhere else.

 

[MattyIce26]

I rechecked my tuning and its actually only about 2 turns on bottom end and 1-5/8s top end. I rejetted the carb for the 701, I put in a 135 main jet.