Quadrajet choke ?

[BackWoodsTracker]

OK, I was going to post that I was missing the fast idle cam and related parts on my dad's carb. But after doing a search, I see there isn't one on boats. My problem is that at cold start up, the choke isn't held closed. It's a 1980 Mercruiser 228 with a Quadrajet 4MV. I finally got the shifting issue figured out, Now I just want it to start easier. What holds the choke closed at start-up?

 

[Bt Doctur]

Re: Quadrajet choke ?

The electric element or a bi-metal spring mounted on the intake manifold

 

[BackWoodsTracker]

Re: Quadrajet choke ?

I take it that spring is shot then. I'll look a bit closer at it. I didn't see any adjustment type thing to it. I'm glad that looks easy enough to change. I'm getting sick of having to hang upside down to work on things!

 

[jtybt]

Re: Quadrajet choke ?

I've found the choke on boats are pretty much unnecessary. On my Q-jet, I removed the choke plate and rod. I just use throttle to warm up.

On the holley(elec choke) it works as intended so I leave it alone.

 

[gadget73]

Re: Quadrajet choke ?

When I worked on these for a living, at least half of the boats I came across had a spring broken off the manifold, missing, or bent around so it couldn't work if you wanted it to. One boat had the spring installed, but the plate it was mounted to that fastened to the intake was rotted away, and the weight of the mechanism was causing the choke to shut randomly when it would move around. The customer didn't want to spend much on it, so I took the broken spring off, and wired the choke to full open. It ran fine afterward.

 

[45Auto]

Re: Quadrajet choke ?

Had a 1987 Q-jet with the manifold-mounted coil spring choke. The shaft in the middle of the coil spring is crimped to the bracket. Crimp on the shaft had worn out and the spring just spun the shaft in the bracket instead of working the choke.

 

[Gary H NC]

Re: Quadrajet choke ?

Many times its the persons starting procedure.Are you advancing the throttle fully forward then back to high idle position before starting?

 

[BackWoodsTracker]

Re: Quadrajet choke ?

I do fully advance the lever and then back it off. The problem was that the butterfly never fully closed. After looking closer at it, the cover over the spring was holding it up. All better now. Cold starts are much better. Thanks again for the input.

 

[Polar_Bus]

Re: Quadrajet choke ?

You really shouldn't need the choke if you boat in warmer southern waters. Try just giving a few strokes on the throttle to squirt some raw fuel into the carb, leave the throttle just cracked open a bit and provided you have an engine in good tune, your engine should fire NO problem.

My 5.7L 2bbr will lite off stone cold with just a bit of throttle, not even any pumping...

The adjustment of the air/fuel screws also plays a big role in starting, and idle engine behavior.

 

[BackWoodsTracker]

Re: Quadrajet choke ?

I wouldn't mind boating in the warmth of the south, but then I couldn't use my snowmobile

 

[proxyx]

Re: Quadrajet choke ?

There's a theory that choke, by pushing more fuel, washer the cylinders from protective oil coat thereby contributing to wear. Many just do without it.

 

[45Auto]

Re: Quadrajet choke ?

There's a theory that choke, by pushing more fuel, washer the cylinders from protective oil coat thereby contributing to wear. Many just do without it.

Interesting theory. So just how do you crank a cold carbureted engine up in Canada if you don't use a choke??

Only way I can think of to do it is pump the accelerator and dump raw fuel into it with the accelerator pump to richen up the mixture (which would tend to put even MORE raw fuel than the choke into it) or use some kind of starting fluid. Starting fluid works because of it's low auto-ignition temperature, I didn't think it was recommended for gasoline engines as a common procedure (except by the starting fluid manufacturers, of course ).

 

[bruceb58]

Re: Quadrajet choke ?

Many just do without it.

Does that include you?

My engine definitely needs the choke when its cold.

 

[Polar_Bus]

Re: Quadrajet choke ?

Does that include you?

My engine definitely needs the choke when its cold.

richen up the air/fuel screws about 1/2 turn, and I bet you would'nt

Of course it's all very relative to ambient air temps in your specific region...

 

[proxyx]

Re: Quadrajet choke ?

Interesting theory. So just how do you crank a cold carbureted engine up in Canada if you don't use a choke??

"up in Canada" suggests what...? that we have icebergs floating in the lakes in August? LOL. we do that the same way you do... "down in LA" haha.

Does that include you?

My engine definitely needs the choke when its cold.

never disabled it... but never been happy with my choke consistency
on Q-jet it does better then on 2bbl (minimal choke binding haha)

Now, that theory is about engine break-in period. Choke not recommended. Probably fuel delivery to rpm/oil delivery ratio is healthier when lever is pushed then with a choke. Not my direct experience but since I've had my 4.3 recently rebuilt I came across this statement, more then once. Look it up on the net. Nevertheless some boaters choose to run without a choke. That's a fact.

 

[45Auto]

Re: Quadrajet choke ?

we do that the same way you do... "down in LA" haha.

We either use the choke or the accelerator pump to richen up the fuel mixture - either way is dumping more gas in the engine. If there's an iceberg handy, we chip off a few chunks to keep the drinks in the cooler cold!

Probably fuel delivery to rpm/oil delivery ratio is healthier when lever is pushed then with a choke.

This makes no sense at all. Are you under the impression that a 4-stroke engine injects oil into the combustion chamber like a 2-stroke? Choke on a 4-stroke has NOTHING to do with any kind of oil delivery. The oil pump drives off the camshaft and pumps the oil to the bearings exactly the same no matter where the choke is.

Look it up on the net.

Tried to. Couldn't find anything at all on it. Got any links?

Nevertheless some boaters choose to run without a choke.

Yep, some also choose to run without marine starters, or marine carbs, or blowers, or bilge pumps, etc. So?? If you want your engine easier to crank, get a working choke.

 

[erikgreen]

Re: Quadrajet choke ?

My engine cranks quite easily, starts fine. I have a Q-jet with a non working choke on a GM 350 block.

I've never needed it in Minnesota.

Erik

 

[BackWoodsTracker]

Re: Quadrajet choke ?

Well, I got my choke working properly and I like it that way. It did run just fine without it, just a bit harder to start when cold. Now I give it 2 pumps and it fires and stays running just great. Before it would take 3 or 4 times before it'd stay running at about 1200 rpm.

 

[John_S]

Re: Quadrajet choke ?

Yep, some also choose to run without marine starters, or marine carbs, or blowers, or bilge pumps, etc.

Well, I wouldn't rate pumping the accel pump vs a choke, up there with blatent safety issues.

 

[proxyx]

Re: Quadrajet choke ?

We either use the choke or the accelerator pump to richen up the fuel mixture - either way is dumping more gas in the engine. If there's an iceberg handy, we chip off a few chunks to keep the drinks in the cooler cold!



This makes no sense at all. Are you under the impression that a 4-stroke engine injects oil into the combustion chamber like a 2-stroke? Choke on a 4-stroke has NOTHING to do with any kind of oil delivery. The oil pump drives off the camshaft and pumps the oil to the bearings exactly the same no matter where the choke is.



Tried to. Couldn't find anything at all on it. Got any links?



Yep, some also choose to run without marine starters, or marine carbs, or blowers, or bilge pumps, etc. So?? If you want your engine easier to crank, get a working choke.

who said engine oil goes into the combustion chamber...? oil is splashed from the bottom...

Don't know how you did that, e.g. 2nd link coming up on Google. Couldn't be more "into the face...", there's is more... http://www.sacoriver.net/~red/breakin.html

makes's sense or not it is out there. Never endorsed that or rejected, just mentioned it so you and others know about that...