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Primer vs Choke
- Thread starter AdamXP800
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CReynoldsMIZ
Well-Known Member
Here is just my 2 cents, don't ya think if the seadoo designers thought a primer was better, they woulda used one? If you ever get a run away lean engine, good luck killing it with a primer. A choke is the only way to kill it. My carbs are set about perfect on my 96 XP (just plain stock settings) and if I let it sit for a month it starts up in about 5 seconds with the choke on. A properly functioning choke I believe is better than a primer. I'm just going to go with the simple fact that if Doc honda, racerxxx, loudoo, JSG, Tonka all use chokes in favor of primers, then maybe I should just keep it that way too. I thought about this when rebuilding my 96, but I didn't and I'm glad l now because once I did have a runaway and damn glad I had a choke
Dr Honda
Well-Known Member
Yep... what he said.
I use the choke until there is an issue, and then I change to a primer.
CReynoldsMIZ
Well-Known Member
Lol kicker you weren't around all summer to hear about the runaways. I'll let one of the techs like dr honda explain, but from what I have heard it's kinda the same thing as a Diesel engine. No spark still runs
Luv2Camp
Active Member
I installed a primer on my 95 GTX. I had to cut one of the barbs off of the forward fitting as it was pinching the line against the airbox and only allowing fuel to prime into one carb...
As far as runaway. I was beside myself when it happened during winterizing. Hit 9700 RPM. Pulled key, nothing, pulled spark plug caps, nothing! switched the fuel switch to off and it ran out of fuel. Noe I know just to give it more fuel if it happens again... Besides almost blowing my engine up, I like the instant starts with the primer...
As far as runaway. I was beside myself when it happened during winterizing. Hit 9700 RPM. Pulled key, nothing, pulled spark plug caps, nothing! switched the fuel switch to off and it ran out of fuel. Noe I know just to give it more fuel if it happens again... Besides almost blowing my engine up, I like the instant starts with the primer...
I quick squirt of fuel from a primer will slow an engine down as well as a choke. Like eddie said a primer is much better for quick cold starts. Removing the choke butterflies and shafts them selves allows for better performance especially if in conjunction with other modifications.
On a stock ski it offers faster starts but comes with risk. Those $20 primers have seals that can dry out in as little as two years. If you draw your priming fuel from the line that you normally run your engine from then it can draw air in and cause the engine to go lean. Just something to be aware of.
The solution on modded skis is to use a primer but feed it off the return line. Now this is a horrible place to find fuel on a cold engine especially if it has been sitting a while. For this reason you must tie strap a loop in the return line and put your primer's pick-up "T" in the bottom so you always have a couple squirts to get it going but never run the risk of drawing air into your feed line.
On a stock ski it offers faster starts but comes with risk. Those $20 primers have seals that can dry out in as little as two years. If you draw your priming fuel from the line that you normally run your engine from then it can draw air in and cause the engine to go lean. Just something to be aware of.
The solution on modded skis is to use a primer but feed it off the return line. Now this is a horrible place to find fuel on a cold engine especially if it has been sitting a while. For this reason you must tie strap a loop in the return line and put your primer's pick-up "T" in the bottom so you always have a couple squirts to get it going but never run the risk of drawing air into your feed line.
- BiRkS_
Active Member
Another thing to add to the discussion. My skidoo mxz 583 (same as seadoo 587) has a primer. No choke. In fact, most SKIDOO's have primers! That would be the only way for me to start it in 1 pull, sometimes 2. Choke would be 5-10 pulls.
IMO Stick with chokes if you use your seadoos alot, if you are going for high performance/it sits a long time, maybe a primer is for you.
OR, I have seen people plumb in a 5/16'' inline primer bulb for outboard engines in the RETURN line (so that you don't restrict the flow to the carbs) This would be my preferred method if you were having problems with cold starting, or the fuel back feeding into the tank while it sits.
IMO Stick with chokes if you use your seadoos alot, if you are going for high performance/it sits a long time, maybe a primer is for you.
OR, I have seen people plumb in a 5/16'' inline primer bulb for outboard engines in the RETURN line (so that you don't restrict the flow to the carbs) This would be my preferred method if you were having problems with cold starting, or the fuel back feeding into the tank while it sits.
Yep, my vintage ski doo's have them, this is the only way with round slide carbs. The carbs on my yamaha srx440 have butterfly carbs, 1980 was the first year for that on a Yammie sled. These have a plunger type choke. You flip a choke lever and the cable pulls a plunger up and fuel is drawn from where the plunger used to be, once running you flip the lever and the plunger is spring loaded to close. Jury is still out on that one.
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- BiRkS_
Active Member
My honda fourtrax quad has the plunger choke AND a primer! its built into the fuel bowl of the carb. Great design, especially when it is really cold in hunting season.
Talking of sleds makes me want to finish my 1979 john deere semi-restoration... Just have to find a new/similar rear shock, as mine was bent, and I can't find a replacement! She's all re-painted, rebuilt 340 cc kohler, new track and bearings, new brakes, new idler wheels, fuel lines, electrical, etc. Unfortunatly P/O used a modified skidoo safari seat, so its not 100% original, but good enough!
Talking of sleds makes me want to finish my 1979 john deere semi-restoration... Just have to find a new/similar rear shock, as mine was bent, and I can't find a replacement! She's all re-painted, rebuilt 340 cc kohler, new track and bearings, new brakes, new idler wheels, fuel lines, electrical, etc. Unfortunatly P/O used a modified skidoo safari seat, so its not 100% original, but good enough!
Dr Honda
Well-Known Member
ok, I need a quick lesson here..........without spark what is moving the pistons up and down on a runaway? I know excess air is coming in and there will be fuel present but that alone will not move the pistons.
When you compress a gas (air) you raise the temp in proportion to the volume. (PV=nRT) This is how a diesel engine runs. (compression ignition)
Generally... a petrol engine doesn't run enough compression to auto-ignite. But, if you couple that with a hot spot in the head.... and it will keep firing.
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kicker
Well-Known Member
thanks Tony, it makes sense to me now, I just couldnt get my head around the no ignition thing.
eddie708
Active Member
very good point never thought about that before. looks like i will be redoing mine this winter. i have also found most of the primer kits come with very cheap fuel line that stiffens up quickly. i normally buy new line before installing it.
AdamXP800
Well-Known Member
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