Chokes not pulling gas into engine

bashr52

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Still chasing a staring issue on my 1980 85 horse.

Issue:
When cold, I can pump up the primer bulb and feel/hear the float bowls filling up until the bulb gets firm. Chokes stay fully closed with cranking, but the engine will crank all day without starting if I let it. If I squirt a little gas directly into the carb throats, and then hit the chokes and crank it, it will fire up within a few turns. Once the engine is warm, it will start up with just a turn of a key with no issue.

I recently replaced the reeds with a factory set, fully rebuilt the carbs (pulled all welch plugs, blew out/cleaned passages, checked float levels, etc), and did a full link-and-sync. No change in starting behavior. I thought maybe there was an issue with with the ignition switch dropping voltage to the ignition while cranking and chokes activated, but I checked the ignition voltage with a meter while cranking and while it does drop a little, it never drops enough to cut out. Compressions are 130, 135, and 135.

The issue appears to be fuel related. For some reason it seems cranking with the chokes closed is not pulling gas into the cylinders.

Anyone have any ideas?
 

GA_Boater

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Are you using the warm up lever or neutral only button?
 

bashr52

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Yes, knob pulled out and throttle advanced to fast idle position
 

Baylinerchuck

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Still chasing a staring issue on my 1980 85 horse.

I recently replaced the reeds with a factory set, fully rebuilt the carbs (pulled all welch plugs, blew out/cleaned passages, checked float levels, etc), and did a full link-and-sync. No change in starting behavior. I thought maybe there was an issue with with the ignition switch dropping voltage to the ignition while cranking and chokes activated, but I checked the ignition voltage with a meter while cranking and while it does drop a little, it never drops enough to cut out. Compressions are 130, 135, and 135

Anyone have any ideas?

Just thinking out loud. Did you check for spark while the engine was cranking cold with choke butterflies closed. That type of ignition relies on starter RPM to spin the magneto fast enough to develop enough current to fire the coils.

My 90hp threw me off a little. The starter on mine was just a tad slow. Pull a plug and I had fat spark. Put all 4 plugs in, no spark. I learned the starter had to develop a minimum RPM to fire. Anything less, no dice. I don't remember the exact RPM, I found an online resource somewhere.

Just wondering if the closed choke butterflies bog the starter down too much.

I assume you visually watch the choke butterflies close. If so, and you have spark, it has to be the carb.
 

Jiggz

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The fact it will start when yo squirt gas directly into the carbs, it's obvious you have spark and compression. Do the following for diagnosis purposes:
1. With the engine started and in idle, try placing the control lever in fast idle position all the way forward. Does the engine rpm increases to about 2000~2500 rpm? If not, the carbs linkage and idle screw settings are not set accordingly. You might want to zero the linkage and set your idle screw accordingly.

2. If engine rpm increases while idling when control lever is place in fast idle position, then the most likely starting problem is the primer bulb. To verify this install a clear fuel filter between the fuel pump outlet and the carbs' inlet. You can just keep the filter in place for future fuel related troubleshooting. A simple and cheap Fram G2 from WM will do. It's more of a troubleshooting tool rather than a fuel filter.

3. When priming, check make sure the clear fuel filter is actually filled at least half way before trying to start. If after this the problem persists, then it is time to check the floats on the carbs to make sure they are not stuck.
 

jerryjerry05

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Try starting while the engine is tilted up.
I had this problem and couldn't figure out why?
​I had one motor tilted up and was running off the other motor.
​I grabbed the wrong key and tried to restart the one I was using.
But I was trying to start the tilted one.
I heard the motor pop and fire.
Turned it off and lowered it and it started right up.
It would restart all day after that.
But if it sat too long it wouldn't start and needed to be tilted again???

I believe the float level on 2 of the 3 was wrong.
​It eventually worked itself out??


The squeezie might be only filling 1 carb??
 

bashr52

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There is a clear fuel filter installed. When pumping the primer gas goes into the filter and with the bulb firm, the filter has gas in it.

Engine revs normally when advanced to the fast idle position.

When the carbs were apart I verified the float levels were all set to spec, and checked the needles were properly sealing/unsealing with the floats both open and closed.

I'll give it a shot when tilted. After the engne has been tilted up for a while, I do notice some gas residue in the intake like it was running out the carbs.
 

bashr52

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Today's update. Primed until bulb was tight, tilted engine to try it. No start still, but gas out all 3 carbs so I know it's priming them all. Pulled the plugs to check spark, all 3 were wet so it's not a gas isue as I thought.

A voltage check with ignition on and chokes activated yielded a 2 volt drop. Throw in the starter and ignition, voltage drops to 7-8 volts. I wired in two relays to check. With the choke relay in, the ignition only saw a slight drop, less than .5 volts. With the starter activated, voltage drop was still down to around 8 volts from the switch through the ignition circuit. I didn't check the voltage on the output side of the relay to see if the voltage drop is enough to activate the ignition relay.
 

hemi rt

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It sounds like your chokes may be set too tight, at room temp and the chokes closed they should be open about 1/8 to 1/4 inch and as soon as the engine starts they should open a little more. The chokes don't suck fuel but make the carbs go to a over rich condition that allows more fuel into the engine for cold starting. If the chokes are fully shut when you try and start it you will probably get a flooded engine thus your wet plugs.
 

bashr52

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Another thing to consider is if I move the controls to fast idle/start position, turn the key to the on position, and manually close the chokes while shorting across the starter relay terminals, it will fire up in just a couple turns. That leads me to believe that the choke settings are ok, and I am getting spark at starting RPM, just not when on the key..... That is while I'm now leaning to a voltage drop across the switch cutting spark while starting. I hate to just start throwing parts at it, but I'm leaning toward maybe replacing the ignition switch to see what happens. I'm trying to rule out the switch though but putting relays inline with both the choke and ignition circuits. If they fix the issue I know its a voltage/spark issue and not fuel.
 

jerryjerry05

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IF?? the motor sparks and turns over with the key then the switch is ok.
Spark tester? Have someone turn the key and you watch the spark.
Possible the choke piston isn't drawing all the way in and not closing the shutters.
WD 40 on the piston and operate it by hand.
Make sure it draws all the way down.
The choke body can be adjusted for a better pull.

​hemi rt : this choke isn't like a choke on a car.
It's either on or off.
When the keys pushed in it should be closed all the way.
Off it's open all the way.
 

Jiggz

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I actually have relay with my choke unit. You might want to visually check the choke operation. With the cowl off, try starting the engine with the choke. Yes, you will initially hear the choke click to indicate it is engaging. But watch carefully, when you place the switch in start position, does the choke stay engaged or does it drops out? If it stays engage, do it a couple of times to make sure it constantly engages.Remember, as soon as the engine starts to cough. You should let go of the choke or re-start it without the choke to avoid flooding it.

In my case, when the battery is not freshly charged, the choke tend to engage and then drops out when starter engages. This is not constant but happens frequently. So I wired a relay using the original green wire as the control wire and connecting the power wire directly to the solenoid large red cable (+).
 

bashr52

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Updated: It's fixed!

Engine is now running the best it ever has since I owned it... To bad I just sold the boat so I can't enjoy it :(

I put the battery on a trickle charger for 2 days and let it get 100% topped off. Wired in the relay for both choke and ignition to eliminate issues with voltage drops while cranking, and it fired up after about 1/2 a revolution. Let it run on the muffs for a few minutes and its super smooth at idle and just above where there used to be a miss/stumble.
 

Jiggz

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Well that's great. And thanks for updating the conclusion of your thread.
 

bashr52

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Update again: Took the boat over to the new owners on Saturday afternoon. Went over everything with him, showed him where everything was, and then showed the starting procedure. Engine fired once when I cranked it, and then just sat there and cranked like usual. Made me look like an idiot, I was just telling him how it was fixed and working great. I pulled the plugs and verified there was spark there when cranking, chokes were closing, etc. All checked out. Wiped plugs clean, and tried it again. No fire. Pulled plugs, they were still dry. Apparently its a gas issue not spark, no gas being drawn into the cylinders.

The only thing that changed since I "fixed" it and had it running earlier in the week was I put the intake box back on the carbs, and the engine was tilted up for 3 days.

We did get it going if I resorted back to the old way of holding the throttles full open manually while cranking with the chokes closed. Once it got gas draw in and fired off, it will start and run off the key all day.

Not my issue any more as the boat is sold and delivered, but still frustrating as it was running so well before I took it over there....
 

Jiggz

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I sincerely would focus more on the priming bulb not delivering fuel into the carbs. But then as you mentioned it's out of your hands now.
 

bashr52

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I sincerely would focus more on the priming bulb not delivering fuel into the carbs. But then as you mentioned it's out of your hands now.

I thought that, but I have a clear fuel filter between the fuel pump and carbs. Pumping the primer bulb shows fuel filling the filter until the bulb gets hard and can no longer be pumped. I pulled the gas line off the top carb to verify fuel got to the bowl, line had gas in it.

It just dawned on my though, I'll have the guy change the fuel filter. It's been on there a while and maybe it has filled up with junk that the primer cannot overcome, but the fuel pump develops enough pressure to force fuel through?
 

Jiggz

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It's really puzzling that after manually opening the throttles with the chokes closed that it will start and will do so for the rest of the day. Which obviously has something to do with the fuel in the carb's bowl. I guess the question is how long does it take to get it started (when cold) in this manner? Two to four cranking over of at least 5 secs each? More? Longer? How long? How many times? If it takes more than 4 times of cranking then it is more of a fuel not getting into the bowls. Check inlet needle or float position.

If it only takes 2~3 times of cranking over but takes longer like 15 secs each cranking, then the same case of low fuel in the bowls but it can also be electrical. Next time you do the starting, do all the starting procedures then pull one of the plug wires and check for sparks or if you have an inline spark tester even better. If there is no spark initially or on the first cranking, you might want to investigate further on the electrical side. Additionally, check the plugs to make sure it is wet of fuel. If not you could have both problems. But you need to eliminate one first to pursue the other.
 

jerryjerry05

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Still sounds like the choke piston wasn't drawing the arm all the way down?

The 2 best days of a boat owners life??
The day he buys it.
Then the day he sells it!!! :)
 
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