The_7

i know the hot start assist slightly opens the throttle valves when you turn the key if the motor is hot - what does this do, would the car not start hot without it and why? i know most people remove it and you can do the same thing by just pumping the gas a couple times - im just wondering what the opening of the throttle valves does. also why dont they need to be opened for a cold start?

RotorMotorDriver

iTrader: (1)

If you remove it, the car should still start just fine. Mine did. I never had to pump the gas. Even cold I just put the choke on and it fired right up.

~T.J.

inittab

Mazda put it there so it would give you something to remove.

82transam

iTrader: (18)

yea basically, its useless, just pull it out

ioTus

iTrader: (5)

Thats not true!! Sometimes it causes the engine to flood after driving it in warm weather! So it OBVIOUSLY does something.

vipernicus42

iTrader: (4)

Lol!! We should call it the Flooder :P

Consider mine removed.. When I put the "new" nikki in, the cable for the hot-start wouldn't fit in the bracket, and if I connected it's power connector, the hot-start motor would perpetually stay on, so out it came!

Jon

Jeff20B

iTrader: (13)

Yeah, just disconnect the power connector and see if it helps. If so, yank it out!

Cody

post a picture of what you're all talking about, so I can break that too.

ioTus

iTrader: (5)

Well, not only the power connector, i'd disconnect the cable, at the hot start assist, just to be doubly sure!!!

Let me see if i can find a pic for you Cody.

~Geoff

ioTus

iTrader: (5)

The hot start assist:

AdrenalifeRX7

Does anyone have a hose that connects to the choke and runs under the car? WTF is this and what does it do for my Weber 48IDA?

Pittdp

I thought that was the cruse control.

Amagi82

i did too at first, but its hot start assist.

The_7

ioTus, why does it flood the engine sometimes?

ioTus

iTrader: (5)

Not too sure, but i'm guessing that it gives the engine too much gas when its hot. I really dont understand why the car needs to be assisted when its hot, tho, i'm still learning about carb'd setups.

~Geoff

The_7

hmmm yea im still learning alot too, i was thinking about it and my guess would be that say the hot start assist opens the throttle to a point where if the engine was running it would go up to 2500 rpm. which means that the engine is taking in the fuel required to run at that speed but since you are just starting it all the time you are cranking and then the time it takes the engine to get up to 2500 it is taking in excess fuel which could flood the engine. im no expert but thats the best i can come up with. any other rotary people who know more than me have any input?

DogBox

Unplug it and leave the cable hooked up. It's a handy way to open the throttles from the engine bay!

1badFB

iTrader: (1)

I believe its the way the fuel atomizes in a hot manifold vs. a cold one. I would guess that when its hot the fuel wouldnt condense as much on the walls of the intake runners when they are cold, and in turn give the engine more gas.

The hot start assist just holds the throttle open a little to allow more air in to compensate for the added fuel getting to the motor on startup.
If you remove it you may experience more flooding, but to get around it just crack the throttle manually a bit starting it when its hot, always did the trick for me.

trochoid

iTrader: (6)

And you dug up a 3+ year old thread for this little tidbit of info? Thank you for using the search function.

Hyper4mance2k

iTrader: (40)

06-14-03
you idiots are on point, and the reason it's there is because compression drops when the temprature increases on rotaries. So with mileage they can be hard to start.

DogBox

Oops. This is what I get for digging through old posts before I'm done reading new posts, and having two dozen windows open at once.

trochoid

iTrader: (6)

Not a problem at all. Shows the value and useage of the search function and how newbs can successesfully use it when I still have trouble finding what I want some days. We just normally poke fun at those who dig up old threads, regardless of it's content or timeliess.

msmcgill

A few years ago, I was having trouble with my (original owner) '84 GS hesitating to start after running it for a while and then trying to restart it while it was still hot. My mechanic diagnosed it as a bad hot-start assist. He couldn't find a replacement, so he recommended removing it and said that it wouldn't be a problem. I agreed. Wrong! When I drive it for longer than a few minutes and try to restart it (especially on a hot day), many times it will not start without allowing it too cool down first. I've been lucky so far and haven't been stranded. It is just a matter of time. Someday, the battery will give out trying to restart it before the engine has cooled off sufficiently. Never the less, this problem is an annoyance and can be nerve wracking when you stop for fuel or a bathroom break out in the middle of nowhere. Full disclosure - I recently moved to the Arizona desert, so it is probably a bigger issue now than it was before. I relocated from San Diego (a cooler desert). Looking for a properly working hot-start assist now.

tommyeflight89

iTrader: (4)

So all the assist does is crack the throttle a little bit off of idle when two conditions are true: A water temp switch is closed (meaning car is warm/hot) AND there is current to the starter motor.

So you end up with a slightly cracked throttle during cranking when the car is already at/near operating temp.

If yours doesn't work, you can do the same thing with your foot, just a small bit of throttle when you are cranking. Whether it is the primary throttle opened up a bit of the resulting accelerator pump shot that helps, I am not sure...

Hesitating to start when hot could be a symptom of other issues. Ignition, fuel, compression, etc.

Next time the car is already warmed up, have someone watch the motor and cable when you crank. If it doesn't move, something is wrong.. switch, motor, relay, fusible link at starter motor.

Then try to start with a slight cracked throttle and see how it goes. If still hard to start I would begin looking at other issues.

t_g_farrell

iTrader: (1)

This can also be a symptom of old caritis. As rotaries age they can get hard to start when hot.