Hard to start

[Jetjack530]

So I am fairly new to the 2 stroke seadoo’s, I have a 97 SPX. It’s got newly rebuilt carbs with OEM parts and a newly rebuilt motor. Both done by well known reliable mechanics in my area. But this ski is a pain in my A$& to start and will not idle. However when I do get it started it runs like new, no throttle problems great throttle response and good power. But it just won’t idle. And weather it’s hot or cold it’s really difficult to start. I have to slightly feather the throttle to start it and if it’s not perfect it won’t start. It’s also the same level of difficulty with a full tank of gas or almost empty tank. Was hoping you folks in here could point me in the right direction. Thanks in advance.

 

[GGuillot]

So I am fairly new to the 2 stroke seadoo’s, I have a 97 SPX. It’s got newly rebuilt carbs with OEM parts and a newly rebuilt motor. Both done by well known reliable mechanics in my area. But this ski is a pain in my A$& to start and will not idle. However when I do get it started it runs like new, no throttle problems great throttle response and good power. But it just won’t idle. And weather it’s hot or cold it’s really difficult to start. I have to slightly feather the throttle to start it and if it’s not perfect it won’t start. It’s also the same level of difficulty with a full tank of gas or almost empty tank. Was hoping you folks in here could point me in the right direction. Thanks in advance.

Adjusting idle hasn't helped? 3000 rpms out the water or on the trailer. Then in the water it'l drop to about 1500. You seem to be having the same issue I had starting my newly completed resto last year hard to start and had to feather the throttle and it wouldn't idle. I reached down and turned the idle screw until it did. Do that, turn the idle screw in a bit until it stays running, shoot for 3k.

 

[mikidymac]

If adjusting the idle doesn't work this symptom is typically a leaking needle and seat flooding the engine when sitting.

 

[Jetjack530]

I have not tried the idle screw. I’ll give it a try this weekend. Thanks.

 

[Farmboy1029]

Where is the idle screw at

 

[mikidymac]

It's going to be on the front carb near where the throttle cable attaches behind the throttle cable bracket.
It is pointing down. It IS NOT the one going into the side of the carb body.

 

[jts32]

 

[Jetjack530]

If adjusting the idle doesn't work this symptom is typically a leaking needle and seat flooding the engine when sitting.

Thanks for the info, i hope it’s just the idle screw. The carbs are fully rebuilt with new mikuni parts. By a Sea-Doo mechanic.

 

[Farmboy1029]

Idles great now but what about a slight bog when nailing the gas

 

[mikidymac]

You are always going to have a little hesitation going from idle to wide open throttle if you just nail it wide open. It takes a little time for the carbs and engine to respond to the huge vacuum change.

It shouldn’t however die or anything like that.

 

[Farmboy1029]

You are always going to have a little hesitation going from idle to wide open throttle if you just nail it wide open. It takes a little time for the carbs and engine to respond to the huge vacuum change.

It shouldn’t however die or anything like that.

Why do I have to hold the throttle wide open to get it to start?

 

[GGuillot]

Why do I have to hold the throttle wide open to get it to start?

You shouldn't need to hold the throttle wide open, are you pulling and holding the choke?

 

[mikidymac]

Never should have to touch the throttle when starting it.

Something isn’t right with your carbs.

 

[Jetjack530]

Never should have to touch the throttle when starting it.

Something isn’t right with your carbs.

Yeah my buddies ski he just hits the start button and after a couple cranks it just starts and stays running. Man I want my ski to do that. After getting mine started it runs like a Champ. Tons of power and good top end. But man it’s a pain to start.

 

[GGuillot]

It’s got newly rebuilt carbs with OEM parts

One way to tell if the mechanics really rebuilt with OEM, it depends how much was paid to do the carbs, I'd be impressed if the dual OEM carb kits w/needle seats were less than $130. Parts alone, not labor... If it's not your carbs causing the hard start issue, I'd check the rotary valve clearance which may cause starting issues when it gets too far out of spec. I'm rebuilding a second ski at the moment, 787 carb 96' GSX, and it too had a way out of spec rotary valve at .020. The 97' GTX with a little higher hours, was even higher at .024. In spec is between .010 - .014. I bring the cover to a local place and it cost me $100 to have the outer lip and oring seal machined to bring it within spec. Checking it is fairly easy to do, refer to the SM, recommend the solder method.

Not saying the mechanics didn't do it by the book, but if it was you wouldn't experiencing the start problems you're describing.

 

[Jetjack530]

One way to tell if the mechanics really rebuilt with OEM, it depends how much was paid to do the carbs, I'd be impressed if the dual OEM carb kits w/needle seats were less than $130. Parts alone, not labor... If it's not your carbs causing the hard start issue, I'd check the rotary valve clearance which may cause starting issues when it gets too far out of spec. I'm rebuilding a second ski at the moment, 787 carb 96' GSX, and it too had a way out of spec rotary valve at .020. The 97' GTX with a little higher hours, was even higher at .024. In spec is between .010 - .014. I bring the cover to a local place and it cost me $100 to have the outer lip and oring seal machined to bring it within spec. Checking it is fairly easy to do, refer to the SM, recommend the solder method.

Not saying the mechanics didn't do it by the book, but if it was you wouldn't experiencing the start problems you're describing.

Right on thanks for that. I’ll have that checked. I paid 185 for parts and labor on the carb rebuild. I’m going to test the idle screw method this week. If that doesn’t fix it, then I’ll take it to the local shop to have the rotary valve checked. And if that’s not it, then I may freak out. That will damn near be everything possible. Besides the computer.

 

[mikidymac]

I would be highly suspicious of those carbs. To do 2 carbs correctly with the correct Mikuni parts you are looking at a minimum of $120 so I can’t see him only charging $60 for labor.

 

[Jetjack530]

I was thinking it was on the less expensive side, but I purchased the rebuild kits myself. And he showed me the old parts he took out. Local water sports shop. Done a lot of work for me on my boat. Hoping that’s why I got the good deal on labor.

 

[GGuillot]

I was thinking it was on the less expensive side, but I purchased the rebuild kits myself. And he showed me the old parts he took out. Local water sports shop. Done a lot of work for me on my boat. Hoping that’s why I got the good deal on labor.

And you purchased needle/seats with the OEM kits? Nothing against the local shops doing the work, but a lot of times they are unfamiliar with some details with the old 2 strokes. Things like a pop off test, don't use the springs in the kit, etc. Syncing dual carbs even baffles some 'experienced' shop mechanics, someone on the other forum I'm on was convinced to switch to a single carb because the mechanic said it's too complex to sync dual carbs.. He actually listened to the guy and did it..

 

[Jetjack530]

And you purchased needle/seats with the OEM kits? Nothing against the local shops doing the work, but a lot of times they are unfamiliar with some details with the old 2 strokes. Things like a pop off test, don't use the springs in the kit, etc. Syncing dual carbs even baffles some 'experienced' shop mechanics, someone on the other forum I'm on was convinced to switch to a single carb because the mechanic said it's too complex to sync dual carbs.. He actually listened to the guy and did it..

Hahaha that’s funny, I’d like to see what that single carb looks like .. yeah I bought a full minkuni rebuild kit for both carbs from SBT. Was going to do it myself. But figured I’d have my watersports shop do it. They specialize in PWC. I just took them the carbs though. I should have taken them the whole ski. They have a water tank they could have tested it in.
Most likely I’ll be taking it back to them.

 

[etemplet]

I was at war with the carbs on my 2 GTXs. Only until I replaced everything with genuine Mikuni parts did the skis cooperate. I hope you did purchase genuine Mikuni parts. I won't install anything else.

 

[etemplet]

I think you are having to hold wide open throttle to get the ski to start because your needle is leaking. Engine is flooded and you're letting in a ton of air to clear it before it will start. I'd prove the carbs are good before I'd worry about the rotary valve unless there is evidence to do so. Good Luck !!

 

[mikidymac]

Hahaha that’s funny, I’d like to see what that single carb looks like .. yeah I bought a full minkuni rebuild kit for both carbs from SBT. Was going to do it myself. But figured I’d have my watersports shop do it. They specialize in PWC. I just took them the carbs though. I should have taken them the whole ski. They have a water tank they could have tested it in.
Most likely I’ll be taking it back to them.

There is your problem right there "from SBT". SBT kits are not genuine Mikuni, they are the crap Chinese kits that cause all of these problems.

 

[Jetjack530]

I think you are having to hold wide open throttle to get the ski to start because your needle is leaking. Engine is flooded and you're letting in a ton of air to clear it before it will start. I'd prove the carbs are good before I'd worry about the rotary valve unless there is evidence to do so. Good Luck !!

I don’t have to hold mine wide open throttle to start. I have to ever so lightly feather the throttle.

 

[Jetjack530]

There is your problem right there "from SBT". SBT kits are not genuine Mikuni, they are the crap Chinese kits that cause all of these problems.

Why is that a problem? They came in minkuni boxes and bags and they were highly recommended by several shops??