1986 Chrysler 125 hp Force falls on its face after a few mins.

[stephens.richard]

it will come out strong after a few min. it will cut out and will only go as a troll. just as a heads up i have all ready checked the following
compression is great
check for spark replaced the last coil due to no spark
rebuilt carbs getting plenty of fuel
took it to marina they set carbs and set timing

 

[foodfisher]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Check fuel tank venting.

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Not sure what that means... I know of the fuel overflow, but not sure about the venting. I am interested to f you dont mind explaining?

 

[Jiggz]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

When it goes to a troll after a few mins, will it come back strong again maybe after a few minutes? What about if you just maintain maybe 2000 RPM, will it still troll? Will it be at the same amount of time it'll take from WOT to troll compare to 2000 RPM to troll? What I'm getting into is if the problem is fuel starvation caused by a faulty fuel pump, clogged fuel lines or fuel filter or even a sticky bowl float on the carbs.

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Let me tell you what happened and you tell me... I had just replaced the #4 coil and took it out on the water. It started right up and (this is a problem I have had quite a bit since i got the boat) as soon as I put it in reverse and it backed out, put it in forward and gave some throttle it didnt want to go... then I backed off to neutral and it stalled. Started right back up and put it in forward and it got right up without a hitch, Not sure about RPMs exactly but they sound about right (dont have a tach, yet) I am pretty sure I have deduced that it is not fuel related... I just replaced all fuel lines, and rebuilt carbs with adjusting floats, as for the fuel pump we replaced the diaphragm--havent checked to see if I put the diaphragm in right--would something like that cause the problems I am having? DRIVING ME CRAZY

 

[foodfisher]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Not sure what that means... I know of the fuel overflow, but not sure about the venting. I am interested to f you dont mind explaining?

Fuel tank is vented to the atmosphere to prevent a vacuum from developing in the tank. Like putting your finger on the end of a straw while sucking on the other end. The vent hose may be plugged by debris of some kind (mud dobber), or may be kinked, or debris clogging pickup tube. I don't understand the process but there are three valves in the fuel pump that may be malfunctioning.

 

[Jiggz]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Let me tell you what happened and you tell me... I had just replaced the #4 coil and took it out on the water. It started right up and (this is a problem I have had quite a bit since i got the boat) as soon as I put it in reverse and it backed out, put it in forward and gave some throttle it didnt want to go... then I backed off to neutral and it stalled. Started right back up and put it in forward and it got right up without a hitch, Not sure about RPMs exactly but they sound about right (dont have a tach, yet) I am pretty sure I have deduced that it is not fuel related... I just replaced all fuel lines, and rebuilt carbs with adjusting floats, as for the fuel pump we replaced the diaphragm--havent checked to see if I put the diaphragm in right--would something like that cause the problems I am having? DRIVING ME CRAZY

Well this post is a little different from the initial post. And you're right with symptoms like the one above, it's not fuel related. It sounds like more of the reverse gear not disengaging when you shift from reverse to neutral to forward while the engine is running. And then when the engine stalls, the gear finally disengages and then when you go forward it works perfectly or normally. You might want to verify the gear shifter and associated linkage from the throttle lever are centered. You can verify this with the engine shut off first and also while running. With engine off, shift to reverse and try manually turning the prop and it shouldn't turn if it's engaged. Shift to neutral and turn the prop again and it should be free wheeling. And do the same for the forward gear. I do not expect to recreate the problem with the engine off but just want to make sure the shifter is centered to start with. With engine running with flushing muffs, (stay clear of the prop! Do not rev engine while on flushing muffs) when you shift to reverse the prop should turn in reverse. Shift to neutral and it should stop. Do the same with the forward shift. If after you shift from reverse to neutral and the prop doesn't stop turning, there is your problem! This could be a linkage problem or clutch dog problem.

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

This is not a problem I only have when shifting... this is in addition to the problem I wrote about to begin with. I can literally start up the engine, take off, get planed out, cruise for about 1/8 mile and all of the sudden it completely stops. That is my main problem at this point.

Runs fine with muffs on...only have this problem in the water.

Although the throttle lever is kind of strange... it is tight and hard to push to WOT I will move from forward to reverse (at times) without stalling. It will go- but it is like I am having to force it. The main problem is the lack of ...go--if that makes any sense. sometimes it will and sometimes it wont. It must be electrical because anything else would be simple to figure out. I think it is a bad CD. I have decided to take it to a marina. I have just about had it with this thing. I have the clymer book for it and I cant make heads or tales of it.

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Fuel tank is vented to the atmosphere to prevent a vacuum from developing in the tank. Like putting your finger on the end of a straw while sucking on the other end. The vent hose may be plugged by debris of some kind (mud dobber), or may be kinked, or debris clogging pickup tube. I don't understand the process but there are three valves in the fuel pump that may be malfunctioning.

Ok I am aware of the venting and that has been checked-thanks for the help though...just not sure there is much help for this old girl anymore. Bout to call it quits, unbolt it from my bayliner and let her sink to the ocean floor!! I will swim back!!

 

[foodfisher]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Sorry for your problems and my lack of ability to help. My motor is an '86 also and with this forums help it is a dependable and strong runner. I paid up for the OEM manual, what it doesn't explain in laymans terms, these guys do. Explain your probs. clearly and help is eminent. Best of luck

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Hey no problem foodfisher... these old girls are beasts I know and I just need a break!! She is testing my mechanical capabilities and stabbing at my pride a little lol! I have read about a few things involving the use of a clear style fuel filter and a basic merc fuel filter. I will start there---stay simple first right!!

 

[Frank Acampora]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Usually, with a failing CD box I would expect complete failure, not intermittent problems. I know you have replaced most of the fuel system, but did you check whether or not there is a screen inside the fuel tank? If there was one, did you check to see if it was clear or clogged? If you have a quick-connect fuel fitting, did you clean out both the male and female fitting? Did you replace the primer bulb? Does it collapse when the engine slows down off plane?

The fuel pump diaphragm can only go on one way. You can not have installed it on incorrectly. However, did you replace the gasket?

Low speed stalling is almost always due to too low an RPM. Typically, because there is less load in reverse, the engine will not stall in reverse but will stall in forward.

However, if the engine did not do this before, then we need to figure why the RPM is too low now before adjusting anything. It could be simply due to fouled spark plugs so the first thing to do would be clean or replace them.

These are all things you need to do yourself. Why pay over 100 bucks an hour for a mechanic (who probably doesn't care about you or your engine) to do these simple checks.

With a knotty problem like this one, to trouble shoot, you must be methodical. Do not assume that a component is bad. You can not use a "shotgun" approach. Eliminate every factor in fuel first because it is the simplest system. Then go on the electrical, starting from simplest--sparkplugs-- to more complex. Once you have a plan of action, then the engine will no longer frustrate you.

Now, you do know you have a problem with throttle and shift linkage. Make your life easier. Fix that before trying to troubleshoot the engine. Remove the cables at the engine end and then see if the control box shifts easily and smoothly. If not, then the problem is with it or the cables, not at the engine. If the box does shift and accelerate throttle smoothly and easily, then the problem is in how the cables are attached at the engine end.

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

no screen in the tank...no quick connect fuel fittings...checked both for leaks though.

replaced primer bulb-but seems like it could be starving. maybe i will change the clear type fuel filter with the standard white merc.

started thinking about all of the things that it didnt do before and what i had done since then.. i changed the fuel line to 3/8 and it was 5/16---guess i need to change that back and see what happens guess it could be starving fuel with a bigger line.

keep you posted thanks for all the help!! I guess i just needed a bit of reassurance!!

 

[stephens.richard]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

ok now we are getting somewhere. Changed the fuel line size back to the original-changed the fuel filter to a merc white style. took it out on the water and it ran good--didnt cut off--period. Idle seems too low though-doesnt seem to want to go full throttle. Looks like simple worked first. Will let everyone know how this turns out after I adjust the idle--anxious to get her back out in the ocean and do some serious fishing!!!

 

[Jiggz]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

ok now we are getting somewhere. Changed the fuel line size back to the original-changed the fuel filter to a merc white style. took it out on the water and it ran good--didnt cut off--period. Idle seems too low though-doesnt seem to want to go full throttle. Looks like simple worked first. Will let everyone know how this turns out after I adjust the idle--anxious to get her back out in the ocean and do some serious fishing!!!

With the smaller fuel lines working it means you had some air leaks with the larger fuel lines. But that's water over the bridge now. As for setting the idle speed you might want to check on the sticky note above by Frank which gives a step by step procedure to set the idle speed, idle fuel/air adjustments and also the WOT adjustments for the carbs throttle valves (butterfly).

 

[jason32038]

Re: 1986 Chrysler 125 hp Force falls on its face after a few mins.

Fuel lines from the tank to the primer and fuel pump should be 3/8". Fuel line leaving fuel pump to carbs and between carbs should be 1/4". Hose clamps with screws work great.