Just a little throttle makes the engine sputter and die

[rderenzy]

Just a little throttle makes the engine sputter and die (reverse too) - but jumping on the throttle it runs great
Then, after a good half hour on the water - the light throttle is just fine and no issues
this never happened before the mechanic took the engine out to replace the timing cover
Happens on the trailer just like the water

When in neutral - idles great.
When shifted into forward gear or reverse - runs/idles great
but as soon as the throttle engages and starts to open up - massive stuttering and will die unless I punch it or pull back, then runs great.

I do not think its a dirty carb, I think something is just out of place or needs adjusted

Here is some pics of the side of the carb - its weird the carb is always open?
and after the top latch comes down w/ the throttle going forward, it never goes back up...?

Also a video of my giving it some slight throttle here
https://youtu.be/ozNdA40X_U8

any suggestions?
i hate to pay big bucks, especially it works well when full or even half throttle (then works normally after a good 30 min on the water)

any help would be greatly appreciated

 

[boltonranger]

Explain the part about the top latch

 

[rderenzy]

first pick, that horitzontal gold piece on the right - that comes down when the throttle is pushed, it then pushes down and it opens up the carb (its down in pic one)
that thing never moves again, no matter where I move the throttle
pic 2 I manually moved it up to show

 

[bruceb58]

You should have just continued in your other thread.

You have a lean condition.

Does it do this when the boat is warmed up or after you just started. Is your choke closed when you first start when cold?

 

[rderenzy]

sorry bruce - when the boat is warmed up, it does NOT do this stalling - I baby the throttle all day after it is warmed up

not sure how to tell on choke, I'm pretty noob

I see, the choke is the gold plate in the carb - its almost like its backwards...if I open the choke manually, it wont bring back closed

 

[bruceb58]

See that plate that is at the top of the carb? Pump your throttle when the engine is cold. It should completely close. Once you start your engine, it will slowly open as the engine warms up.

 

[rderenzy]

earlier today, when running on muffs it opened WIDE up when I put it in gear and push throttle forward - well did this when I was running on muffs and it would never close
So when I first started it, I'm quite sure the choke 100% opened, if not it 100% opened when I gave it a little throttle

I just went out to the boat, cold - choke was closed. when I moved it to WOT it opened very very slightly
when I returned to N - choke closed
it didn't budge until I was WOT

 

[s.hadley81]

As Bruce said choke should be closed when it's cold and slowly open as it heats up, when you open the throttle when it's cold the choke plate should only open around 5/64" that's the choke unloader. It sounds like your choke is working, also as Bruce said when you start it cold do you advance your throttle to set the choke? Also are you letting the motor warm up before throwing it in gear

 

[achris]

Rich up the idle mixture screw 1/4 turn. ie, screw it anti-clockwise.

 

[rderenzy]

i'll play w/ it again tonight -
So to answer some questions - last night, as soon as I shifted it in gear and gave it the lightest throttle, the choke opened 100% - the tab on the right pushed all the way down forcing the choke up to 100% (see the pic)

normally when I start it, I do not throttle or prime it, starts right up

achris the idle mixture screw - that is the screw on the throttle cable right? the one that has the screw that touches the round plate that moves?

 

[jimmbo]

I think you should get a book on Rochester Carbs.

 

[bruceb58]

normally when I start it, I do not throttle or prime it, starts right up

Well..that is problem #1. You aren't setting the choke.

 

[rderenzy]

Well..that is problem #1. You aren't setting the choke.

well shoot - i didn't know i had to
so every cold start, i should push the throttle all the way forward, and then back to neutral, then start? but when engine warm, just start?

 

[bruceb58]

well shoot - i didn't know i had to
so every cold start, i should push the throttle all the way forward, and then back to neutral, then start? but when engine warm, just start?

You don't need to push it all the way forward. Do a test where you have someone look at the carb while you advance the throttle and see where it is when the choke closes.

 

[rderenzy]

but isn't that the problem? at cold its closed - , at N its closed, when i get the throttle to about 75% all of the way, it opens to a small gap - but if i bring back to N, it closes

so....? not really sure what i'm supposed to do before starting the boat

i've always started the boat in N, and it normaly fires up first try - if it doesnt, then i prime it by pushing throttle all the way down adn then back to N and fires right up. boat wont even turn over w/o being in N

 

[bruceb58]

You can have the throttle advanced and still have it in neutral. Depending on the control you either push a button or pull out on the lever.

 

[rderenzy]

ah, yes i see, i have a button.

but you wanted me to push the lever until it closed, then start the boat..
well its always closed at N

 

[bruceb58]

Earlier you said it wasn't closed when it was cold.

Either way, I am not surprised you get hesitation when it is cold and the engine hasn't warmed up. If it works fine when it is warm, I am not sure I would worry too much about it.

 

[rderenzy]

Yeah I'm no too worried about it.... But try leaving the dock at full throttle or it dies.... Feel like a turd

 

[bruceb58]

Like I said before, sounds like your choke isn't operating or adjusted properly.

Feels like I am talking to myself here!