1997 Force 120 HP Starting At WOT Only

[jay2670]

Hello, I am having a problem with my 1997 120hp Force outboard that has me pulling out my hair and looking for some more advice. Well to start with I am a troller on Lake Erie and that is what i was doing on the day my problem started. That morning I was running hard about 3/4 throttle and went out about 8 miles. Then i slowed way down to in gear idle and started trolling. About five minutes into trolling my engine just stalled. So I thought no problem and tried to restart. The engine would not start. I replaced the spark plugs with hope this would correct my problem. My batteries eventually died. So now I am wrapping a rope around the fly wheel and pull starting it. Found later I could get it to fire with throttle wide open but would stall if I try to bring throttle back down to engage forward gear. Had to be towed in. Since I brought it home I have checked compression and all cylinders are around 120, pulled both carbs cleaned them then noticed fuel coming from air silencer side of bottom carb after attempting to start. Replaced floats and needle valves and rebuilt the fuel pump. I have also replaced water fuel separator and all four plugs again. Now my problem is a little better because I am not spilling fuel from the bottom carb but i still can only start and run at WOT. Do anyone happen to have any other suggestions as to how I may correct this issue?

 

[pnwboat]

Re: 1997 Force 120 HP Starting At WOT Only

Take a look at your reed valves. Look for a broken reed valve petal.

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

Thanks for the suggestion I will pull the carbs and check them out tonight. I was unsure just what those reed valves we for. I am not real knowledgable about these outboards, I always had I/O's and never had this much headache.

 

[roscoe]

Re: 1997 Force 120 HP Starting At WOT Only

Have you checked for spark, on all 4 plugs?

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

yes I have good blue spark

 

[pnwboat]

Re: 1997 Force 120 HP Starting At WOT Only

The reed valves act as a one way valve that controls the flow of the air/fuel mixture from the carbs into the crankcase and eventually into the combustion chamber via the bypass ports. They're kind of like the valves in a four stroke motor. It's common for the petals to break in the later model force motors.

 

[Josh P]

Re: 1997 Force 120 HP Starting At WOT Only

Hey jay if you need any help let me know im in brunswick, i as well have a force mine just a 91 but a 120 let me know, i am buying a dva for ignition testign next week, if you need anything PM me.

 

[omcgreasemonkey]

Re: 1997 Force 120 HP Starting At WOT Only

jay at wot the timeing is advanced test the continuity on your trigger they fail sometimes and wont read low rpm

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

All I can say is this web site is great and thanks to all has given input. I pulled the intakes of this past weekend and found a broken reed valve behind each manifold. In a desperate attempt to get my hands on one Saturday with no such luck. The reeds appeared to be replaceable but the dealer only sells the entire block at $86.00 each. I purchased used on ebay cheap and will fit the reeds into my block. So with any luck this will be my problem. I also looked at my stator yesterday it showed 654 ohms between the green/white and white/ green wires anyone know if that is acceptable? I will test the trigger tonight and post back my findings. Thanks for everyone?s help.

 

[omcgreasemonkey]

Re: 1997 Force 120 HP Starting At WOT Only

that reading on the stator is fine the trigger only reads ohms if no signal it may not be telling the pack to fire

 

[pnwboat]

Re: 1997 Force 120 HP Starting At WOT Only

You won't get a reading on the trigger on the 1996 and later ignition systems using the CDM coils/ignition modules with an OHM meter like you do on the earlier ignition systems. The earlier triggers consisted of a small coil and you can read the resistance of the wire with an OHM meter. 1996 and later, they used a solid state "Hall Effect" transistor to detect the trigger signal. OHM meter reads open when reading the trigger on these ignition systems.

To get around this problem on the later model triggers, you can take a rare earth magnet and place it by one/each of the four Hall Effect sensors on the inside of the trigger assy. The meter will read continuity as long as the magnet is placed right at the sensor, and you have your meter leads on the correct pair of wires with the proper polarity. Move the magnet back and forth past the sensor and you'll see the meter reading go from infinity to continuity. Might take a little bit of trial and error, but it works.

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

OK I am not sure about this magnet thing.. Rare Earth Magnet is this just a normal magnet say from a speaker or somthing? Or can I buy one of these. Im assuming I will need to pull the flywheel from the power head,is this correct?
Does anyone feel that my broken reeds are my problem because when I get them Im wishing this will correct my issue, but I have my doubts that it somthing more. So I will look at all suggestions.
I checked for good spark in this matter. Pulled all 4 plugs so that the power head would turn quickly but no faster than it would idle. One wire at a time I inserted a plug and cranked her over while the plug rested against the engine. I have very bright blue spark. So what Im asking wouldnt this be an good indication that my trigger functions at low rpm?? Thanks again for the great info you guys are providing.

 

[pnwboat]

Re: 1997 Force 120 HP Starting At WOT Only

I wouldn't worry about the spark, trigger etc at this point. I'm pretty confident that the broken reeds are your problem. I've worked on several 1996 and newer Force 120HP motors where broken reed petals cause the exact same symptoms that you describe. Replacing them fixed the problem. Triggers are not a high failure item. Stator is more likely to fail than the trigger. If you're getting a good blue spark, then you should be good to go.

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

Thanks pnwboat I am real happy to hear this may be my problem. I will keep you all updated here in a few days.

 

[Gone4two]

Re: 1997 Force 120 HP Starting At WOT Only

Yep, I am 99.95 percent certain that it is your reed valves. I had the same problems with my 97 force (plus a few more). If you read my post "97 force 120 multiple problems" you will see all of the problems that I had with mine. I think that my later problems all stemmed from the broken reeds. What ever you do, do not quick shift from high nuetral into gear. It will likely shatter your shift paw in the lower unit. If this happens, be prepared to dish out the bucks for gear parts. I ended up replacing all four reed blocks (although only two were broken), because in my mind, it needed to be done. You may also want to replace all of your fuel lines (including the 1/8 recirc lines). Hope all turns out well! Please post after you fix!

Gone4two

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

Problem is corrected, and thanks to all you great people here on this form. I had one broken reed behind each carb. Dealer would only sell me the whole block for $89.00 each block. I notice I could see light if I looked into the back side of the block even on the reeds that were not broken. So I flipped all the good reeds over and this made them seal up tight. I could not obtain just the reeds without buying the whole block so I purchased used ones on ebay and waited for them to arrive. After three days of waiting I recived a email saying my money was refunded and the were damaged???? So what I did is made my own by buying some 1095 spring steel and my friend wrote a program to burn them on a laser table at his work. I installed the two homemade reeds and it fired right up. This motor has never ran so good in the the 3 months I have owned it. So what I have learned is if you have fuel blowing out of the carbs and it will not start well or rund poorly check the reeds.
Thanks again!!!!!!!!

 

[lucida]

Re: 1997 Force 120 HP Starting At WOT Only

So what I did is made my own by buying some 1095 spring steel

Jay, where do you buy the 1095 spring steel?

I had my reed patel broken like this:

 

[jay2670]

Re: 1997 Force 120 HP Starting At WOT Only

Lucida I bought the spring steel from McMaster Carr. I used the .010 thickness. I tried to cut it with shears but it does twist it a bit and it can be drilled. Yours are the same shape as mine although I think your reeds are all one. My reeds are four peddles on each side like yours but mine are not one piece. It would even be more difficult to cut yours by hand. But yes that big nasty hole looks like mine did. Did you find you missing part? I did not but I have 120 PSI on all four cylinders so I guess Im still good.

 

[lucida]

Re: 1997 Force 120 HP Starting At WOT Only

Jay, thanks.
I am thinking to use dremel and small cut-off wheel disc to do the job.

Is this the one you purchased?

http://www.mcmaster.com/#grade-1095-steel/=9hossl

Steel
This product matches all of your selections.

Part Number: 9014K22 $14.56 Each
Material
Tough Wear-Resistant 1095 Spring Steel

Alloy
1095

Finish/Coating
Polished (Blue Finish)

Shape
Sheets, Bars, and Strips

Sheets, Bars, and Strips Type
Plain

Thickness
.010"

Thickness Tolerance
?.0007"

Length
25"

Length Tolerance
+3", -1/2"

Width
6"

Width Tolerance
?.06"

Tolerance
Standard

Temper/Condition
Full Hard Temper/Cold Rolled Condition

Hardness
Rockwell C44-C51

Application
Shim Stock

Specifications Met
American Society for Testing and Materials (ASTM)

ASTM Specification
ASTM A682

WARNING
Hardness is not guaranteed and is intended only as a basis for comparison.

 

[pnwboat]

Re: 1997 Force 120 HP Starting At WOT Only

Jay2670, if the other reeds were warped to the point that you could see light, I would seriously think about replacing them too. Maximum allowable gap is .010 inch. A gap wider than .010 may indicate that the steel material has fatigued and it's only a matter of time before they break too. Don't know why, but the 1995 and later 120HP motors have a tendency to break reed petals. The reed valve assy. in the earlier motors seem to last forever.