Another 1997 Force 120 Reeds problem

Jiggz

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In conjunction with PNW's suggestions, next time you go out on the water bring with you a spray bottle with fuel-oil mix in it. Doesn't have to be full maybe 1/3 or 1/2 full. With the cowl off, ran the engine and when you try to go WOT and engine bogs down or would not go above 2600 RPM, spray fuel oil mix directly into each carb. (You will need to remove the air covers to do this and make sure you are clear off shore and traffic. Base results on the following for each carb's reaction.

1. If there is no effect on the carb, i.e. no increase in rpm or no decrease in rpm - both cylinders fed by the carbs are not firing. Troubleshoot for sparks. However, there is also a possibility the throttle is not synch properly (it happened on one of the threads not too long ago) wherein it is wide open even at idle causing too rich of a fuel air mixture to start with. This can be indicated by overly fuel wetting spark plugs.
2. If there is an increase in rpm - there is fuel starvation on the cylinders fed by the carb
3. If there is a decrease in rpm - it means the carb is operating properly and due to over rich fuel air mixture starts to misfire.

Now this is where it gets tricky. Since there are two cylinders fed by each carb, you will need to isolate the one from the other. And you can do this by pulling the plug wire on one of the cylinders affected and do the spray test again. In this manner, you are testing one cylinder at a time. You will do this only after you've done the preceding so you know at least where the problem area is. Try not to keep the plug wire disconnected unnecessarily or in short replace it as soon as possible to protect the ignition system.
 

blackd

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Good advice guys. Will do those tests and also test that ole primer again. I looked closely at the motor and found one of the recirculation hoses pinched under the edge of the fuel pump. As I understand it that might hurt idle but not WOT performance.
 

Jiggz

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A clogged fuel recirc or pinched for that matter will affect both idle and WOT except for the idle it will take awhile. With clogged recirc eventually the affected cylinder will be running really too rich all the time.
 
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blackd

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Even another update! The boat hasn't left the yard as yet to do the on water testing, but did some testing on muffs. Checked spark, again. All OK. Put 2 fingers over mouth of top carb while running, and noticed that it would run better, but still not go to full RPMs. Fuel starvation! So looked at the clear filter and it was staying full, so starvation appears to be after filter. Dropped the fuel bowl of the top carb to check that float went to bottom. It did. I plan on replacing the fuel lines from the filter forward and see what happens.

On a side note. I found four 5 petal reed plates on that ole auction site, and bought them all for south of $50.
 

jerryjerry05

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May 7, 2008
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IF??? The key slipped at all your motor probably wouldn't run???
You follow the procedures for static timing?
I think they are in one of the top posts in this section.
 

blackd

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jerryjerry05, I pulled the flywheel and visually checked the key and components already. Everything looked fine. I also did static timing. The motor starts, and idles better than it has in years. I even started it in the last round of testing without the primer connected to assure it wasn't leaking. It wasn't, and It was after that test that I tried the two fingers. Top carb seems to be the worst. BUT, STILL TO BE DETERMINED! I am a little gun shy at this point.
 

pnwboat

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I don't know blackd but it looks like you've probably covered all bases unless there's something that you over looked. Might have a piece of crud in the fuel inlet of the upper carb restricting the flow of fuel? I don't know.
 

Jiggz

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I recommend, you verify the position of the throttle on the top carb in reference with the other carb and also with the control lever in WOT position. If both are correct, then with the fuel bowl off, shoot the top carb with carb cleaner using the little red straw focused on both of the jets and also the inlet port and needle. If the jets and inlet ports are clear, you should see the carb cleaner shoot through. Heck, while at it you might as well do the same with the other carb. Test again.
 

blackd

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Penultimate update (I hope). Replaced all fuel lines from fuel pump to carbs, and what is becoming my MO, broke one of the fuel line barbs on the lower carb. Its ordered, but before breaking the connector started and ran the motor on muffs. I found the motor running poorly at the low to high speed transition point, ~mid 2000s RPM. When throttle was advanced the motor ran somewhat better, but the top carb still was not pulling as hard as the lower. Running mostly on the lower carb past high idle.

Took them off, and am soaking them until the replacement fuel line connector arrives. I also replaced the newer reed blocks with the older set I bought for ~$11.50 ea. Its sitting in the yard all together minus carbs waiting the connector and re-cleaning of the carbs.
 

pnwboat

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Well there is one other thing that you may want to check out since you have the carbs off and soaking. Clean out the idle by-pass tube. I use a piece of copper stranded wire kind of like a pipe cleaner. May have to remove some of the strands to get it to fit into the tube. Remove the idle mixture screw, run the wire all the way up a couple of times. Take some carburetor cleaner and squirt it into the tube from the bottom and it should spray out of the idle mixture screw hole.
 

blackd

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Another self created problem! While inspecting the carbs yesterday after writing the above update, I noticed a missing high speed jet. I need to confirm, but I think it was on the lower carb and not the upper. A new jet is on its way as I write. I remember knocking some parts off the bench, and thought I had found all of them, but the float pin. I replaced that with a small cotter pin I had, but that is on the lower carb. That too is on order. Man-o-man. I'm my worst problem

Went back and scoured the floor for 1/2 hour and found the original jet. It's now installed. Still can't find the float pin.
 
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blackd

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I've given up. It goes to the mechanic tomorrow. The old reeds seem to make it run worse. The carbs are clean.
 

blackd

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Preliiminary report from the mechanic, BAD GAS, upper carb leaking, leak down test showed one cylinder 16% less than others. They said it will probably rise after doing a decarbonize. They are emptying the tank and purging the fuel system, and will fix leak in carb, then take it out and adjust everything under load.

The BAD GAS probably started whole cascade of events.
 
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blackd

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Sep 27, 2013
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My final report: $700 for new plugs, rebuilt carbs, new gas filler, new water separating filter, complete gas tank cleaning, run and adjust under load. I am happy! This is the first major expense in 15 years of use. That breaks out to less than $50/year. That's not to say I haven't replaced the filter/separator each year. I did see a pictrure of the gas it was AAWWFFUULL!

Thank you, all for your help. Now I will check the weather to decide winterize or one more fishing trip.
 
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