difficult to start f100

strokersquid · Oct 27, 2012

is there a choke or enrichment system for an f100 ? does it work by pushing in the key while starting ?

Georgesalmon · Oct 28, 2012

Re: difficult to start f100

What year? My F50 does not have a manual choke, its automatic.

Capt Ken · Oct 28, 2012

Re: difficult to start f100

We do need the full model number. Some early models did have chokes.

strokersquid · Oct 28, 2012

Re: difficult to start f100

rats, i was just there and i did not think to look

mommicked · Oct 30, 2012

Re: difficult to start f100

I have a carbed 03 F90 and yes it has an enrichment system that is activated by pushing in on the key. I turn the motor over a few times and then press and hold the key a few secs, wait a few secs, then press/turn the key and it usually starts right up when it's cold outside. I did have trouble recently w an old, weak battery. The new, more powerfull battery made a big difference in the starting at all temps.

this info may be untrue ( pushing in on the key ) but it seems to work on my motor to make it start faster especially after not cranking it for a month or more, or on cold days.

99yam40 · Oct 31, 2012

Re: difficult to start f100

YAMAHA MANUAL STORE

I would recommend everyone that owns a Yamaha motor to read the owners manual so they know the proper starting procedure.

I have never seen a Prime start enrichment system that needed someone to push in on the key for it to operate. But I have not looked at that many

Capt Ken · Oct 31, 2012

Re: difficult to start f100

Is there a choke pull on the lower corner of the front of the engine. That will tell you quickly if the engine has a manual choke or not.

mommicked · Oct 31, 2012

Re: difficult to start f100

99yam40 said:
YAMAHA MANUAL STORE

I would recommend everyone that owns a Yamaha motor to read the owners manual so they know the proper starting procedure.

I have never seen a Prime start enrichment system that needed someone to push in on the key for it to operate. But I have not looked at that many

I found no instruction for pushing the key in to activate the choke on a 4 stroke in the online owners manual, it says it is automatic. However, I don't have the original owners manual for my engine and wonder if my switch is worn out or something and when new needed to be pushed in to turn it. I swear my motor starts faster if I push in on the key first, as opposed to just turning it, which it will do w/o pushing it in.

strokersquid · Nov 1, 2012

Re: difficult to start f100

i bought it used and i do not have an owner's manual. it seems awfullly difficult to start , but as i said once it warms up it's good for the day. i heard on other forums that some motors have this feature and i' m hoping that's the reason i'm having so much difficulty.
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strokersquid · Nov 1, 2012

Re: difficult to start f100

i just found an online manual for a 2 stroke yamaha 115 and indeed that's what you do to start the engine, push in the key to activate the choke. now i know. the picture of the control box is the same and so is the picture of the key.

99yam40 · Nov 1, 2012

Re: difficult to start f100

That is not the manual for your 4 stroke motor, look up your motors manual in the link I posted

Capt Ken · Nov 1, 2012

Re: difficult to start f100

I can tell most here has not looked at an owners manual lately. They are more about boating safety than operations of the engine.

99yam40 · Nov 2, 2012

Re: difficult to start f100

Could be,
but mine says to turn key to start, nothing about pushing key in to energize anything. And it is a Prime start model

strokersquid · Nov 3, 2012

Re: difficult to start f100

Capt Ken said:
I can tell most here has not looked at an owners manual lately. They are more about boating safety than operations of the engine.

yes and the manual i saw the first several pages were about safety and were identical to the owners manual for my 2005 yamaha waverunner !

strokersquid · Nov 3, 2012

Re: difficult to start f100

99yam40 said:
Could be,
but mine says to turn key to start, nothing about pushing key in to energize anything. And it is a Prime start model

must be somewhere to see a manual without paying $20. i can push the key in on mine so i will try it this weekend if i take it out. why would a manufacturer make a key you can push in and turn for no reason ?

99yam40 · Nov 3, 2012

Re: difficult to start f100

Try this site, should be able to read the manual if motor is new enough
Owners Manuals | Yamaha Outboards

That switch and controls were made to work on many different motors some with chokes some without

Capt Ken · Nov 3, 2012

Re: difficult to start f100

Yamaha did not use Prime Start on any four strokes. You will find that only on the smaller 2strokes. If its not fuel injected, then it has a choke.

99yam40 · Nov 3, 2012

Re: difficult to start f100

That is strange, as the 1999 to 2003 F100 shows a Prime start assembly in the part break down of carbs

seems like OP still needs to post a model # so we can find out what motor he has

mommicked · Nov 3, 2012

Re: difficult to start f100

99yam40 said:
That is strange, as the 1999 to 2003 F100 shows a Prime start assembly in the part break down of carbs

seems like OP still needs to post a model # so we can find out what motor he has

Yes, my 03 F90 motor and manual have them . I ordered a manual for my 03 F90 but received one for an F100. I assume they are almost the same or same manual from compareing diagrams in the book w my engine. My F100 manual lists Primestart starting enrichment in the general specifications list. In the carberator section these assembles are called Electrothermal Valve units, #1 and 3 carbs have them on my motor. My motor cold starts ok w/o pushing the key when temps are in the 70-90 degree range but after 2 or 4 trys. It will start w just a bump of the key when the engine is warm out on the lake, w/o pushing the key. When it's colder pushing the key in, momments before trying to crank it, helps it start much smoother and faster. Before i started pushing on the key it could take quite along time to crank in 30-50 temps and would die or idle very rough for several mins before smoothing out. It took me a few years to figure this out. :facepalm: Strokersquid you can check you motor for these assemblies, they are about 6 inches long and mounted to the top and 3rd down carbs and have 2 wires going to each one.

Capt Ken · Nov 3, 2012

Re: difficult to start f100

With the prime start system, the push to choke does absolutely nothing. Also with the prime start, advancing the throttle de-activates it.

difficult to start f100

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