Need Help With Force Motor

[brianvolt7]

Re: Need Help With Force Motor

Here is what happened:

I went ahead and tried to start it with full throttle and an atomizer bottle of fuel. I jumpered strait from the battery to the solenoid, key on.

After several attempts it seemed like it was trying to go when I choked it, but just wont fire.

What is a reed valve and where is it located? If these are the valves in the carb, I just went through them. Or are they behind the carb?

So even though I checked each plug against the block and got an arc, when in the block they may not be firing? Am I understanding this correctly?

 

[pnwboat]

Re: Need Help With Force Motor

Yes you may be correct about the spark, however, it's unlikely that both CD modules would go bad causing weak spark on the plugs. I wouldn't rule them out, but you have been able to get the motor to run on occasion for 5 - 10 seconds, so I would think that they're probably OK.

The reed valve assy. (#29) is located under the carburetor adapters. See the diagram below. There is 4 of them on your motor. The reeds themselves (#30) are thin flexible metal or composite material that act as one way valves for the fuel mixture. It is important for them to seal properly in order for the fuel mixture to flow properly.

http://www.boats.net/parts/search/Merc2/Force/120%20H.P.%20%281990-1994%29/0E000001%20THRU%200E093699/REED%20PLATE%20AND%20PRIMER/parts.html


One other question. Have you checked the fuel flow by removing the fuel inlet hose that goes from the fuel pump to the bottom carb? Squeeze the primer bulb and you should get a really good squirt of gas.

 

[brianvolt7]

Re: Need Help With Force Motor

Sounds like if it is the reeds its major overhaul time. I did check the fuel supply, disconnected at the bottom of the carb and cranked the motor and got lots of fuel squirting from the line.

Do you think fuel coming out of the front is an indication of bad reeds?

I have read some things about DVA testing, is this necessary?

 

[pnwboat]

Re: Need Help With Force Motor

Actually reed petals are pretty simple to change. Simpler than rebuilding the carburetors. Just have to take a few more things off after removing the carburetors.

Lets try one more thing here. Remember the kill circuit wires on the terminal block that is located close to the starter? They're either white or black/yellow. They should be located at the third position down from the top. There should be two wires that come from the CD modules, and one that goes to the wiring harness. Disconnect the two that come from the CD modules, separate them and put a piece of tape on them to keep the from touching each other or anything else. Try starting it.

 

[brianvolt7]

Re: Need Help With Force Motor

Actually I disconnected these already and have them taped off. So this is how I have been trying to get it to start. Any other ideas? I have to say I am a little leery about opening up anything on the engine itself, I have rebuilt a couple of engines before on cars but have not done this with a boat motor. Do I need any special tools to get to the reeds?

Also I noticed that the collar on the timing adjustment screw is cracked horizontally all of the way across, Is this a cause for concern?

 

[pnwboat]

Re: Need Help With Force Motor

Very simple to get to the reed valve assy. No special tools required. Just have to be careful about damaging the gaskets when you pull the reed valve assy out.

Only thing that would really concern me is if it was cracked in a way that would prevent it from holding the timing setting. There's not a lot of stress on the plastic piece. Doesn't take much pressure to move the trigger assy. Which is what that piece is connected to. It should look like to piece below. Is it the plastic piece on the left or right in the picture?

 

[pnwboat]

Re: Need Help With Force Motor

Here's a picture of the reed assy. out of a late 90's motor. It has some after market composite material reed petals. It may not look exactly like yours, but you should get the idea. The petals themselves should not be broken or bent. They should lay perfectly flat. Last picture is of the factory metal petal itself. This is the part that actually breaks or bends.

 

[brianvolt7]

Re: Need Help With Force Motor

Easier than I thought, I got to the reeds and they look good, they are gummy though. I am going to finish up cleaning them tomorrow. I ordered the new gaskets so I should have them sometime next week to reinstall them.

 

[pnwboat]

Re: Need Help With Force Motor

I also think you really need the timing light too. Compression tester wouldn't hurt either. You don't havr to purchase them. I'm pretty sure that Autozone will loan you these for a security deposit. When you return them, your full deposit will be returned.

 

[brianvolt7]

Re: Need Help With Force Motor

Reed valve report
Intake 1, 4 reeds stuck
Intake 2, every reed stuck
Intake 3, 2 reeds stuck
Intake 4, all but one stuck
This is assuming that you should see a sliver of light through the normal reeds, is this correct? The stuck reeds were sticky stuck and took some pressure to unstick them. Don?t worry though I was extremely careful when working with them, did not damage them at all. Could this have been the problem?

I ordered the timing light and compression tester on Thursday so I should have them by mid week. I have also ordered 4 new reed valve gaskets, I ripped 2 of them.

 

[brianvolt7]

Re: Need Help With Force Motor

The timimg bolt picture you posted shows the piece on mine that is cracked. It is the plastic piece on the left and it is a horizontal crack and goes all the way accross. Should I replace or possibly superglue?

Also, do you know if there is a feeler guage setting for the reed valves? I am hoping that the little sliver of light is normal and they are not all bent.

 

[pnwboat]

Re: Need Help With Force Motor

I'll let you use your judgment on what to do with the cracked plastic piece. Sounds like the locking nut was over tightened and cracked the plastic. At this point, I don't think it's a show stopper, however, it probably wouldn't hurt to at least super glue it for the time being. As long as it doesn't show signs of movement it'll probably be OK for now. There's not much pressure on it.

If the reed petals are stuck closed, it will definitely affect the engine. Question is, were they stuck hard enough to prevent them from opening when cranking the motor? Kind of hard to tell. I can say this. If they were in fact stuck closed, then the motor will not draw in the proper amount of the fuel/air mixture to operate. It will not run.

From what I can gather in the Clymer manual, it shows that maximum gap is .010 in. Sounds like you should be OK

 

[brianvolt7]

Re: Need Help With Force Motor

Yes the ones that were stuck were stuck hard enough that I don't think they were opening at all. They actually popped loose when I applied pressure. I would say they felt like glue when it is almost set.

 

[PaulO]

Re: Need Help With Force Motor

I reckon the engine is almost ready to fire...?

I could be wrong?

 

[pnwboat]

Re: Need Help With Force Motor

If I were a betting man, I would agree with you PaulO!

 

[Jeremy90bay]

Re: Need Help With Force Motor

This has been a great thread. Lets hurry up and get those gaskets and give it a try! I feel like im watching one of those sitcoms that keeps putting " to be continued......." at the end. HAHAHA

 

[brianvolt7]

Re: Need Help With Force Motor

The anticipation is killen me. I have cleaned all the old gasket off to the reed assembly, the plate and the intakes. All I need now is the gaskets.

I am also restoring the interior so today I will be working on that.

 

[pnwboat]

Re: Need Help With Force Motor

All I can say is that you inability to get out on the boat doesn't seem to be affecting your ability to catch some trout!

 

[brianvolt7]

Re: Need Help With Force Motor

Trout, bass, salmon, steelhead, bluegill, striper, sturgeon. If it swims, I am hunting for it from boat or bank

 

[brianvolt7]

Re: Need Help With Force Motor

pnwboat,

I noticed on a picture you posted on another one of my threads a red wire coming from the top of your motor. What is this? I don?t have this on my motor.

Also I got my timing light today, I don?t know how to use it but I got it. I think the motor needs to be running, doesn?t it?