Chrysler 1977 135 dies if more than 1/3 throttle

[seattle scott]

Engine ran great for several outings this summer. Then during a fishing trip after running at all speeds for an hour, engine would die/cut out if opening up past about 1/3 throttle. Would be hard starting after, but would idle and would run perfectly smooth at high idle. We made it back to the ramp with the 5 hp. I have 120 psi when cold in all cylinders. Disconnected the fuel line into the carbs and got a great flow when cranking with the plugs out. I then re-installed the plugs and put an inline spark tester on each wire. with the engine running, all wires had a weak ( tester light hardly lit up) and intermittent illumination. I then took the dist cap off and noticed that 2 of the spark plug wires ends had corroded ends with a blue gunk on them 9 like you sometimes see on battary terminals) . I replaced all the plugs and wires except the high voltage wire from the coil. I get the same result with the spark tester with new wires/plugs. the coil wire end in the distributor cap looked clean and bright. I got shocked a couple of times with the new and old spark plug wires when making sure the connections to the tester were good with the engine running. With the engine running, when I pull off the bottom #4 plug wire the engine dies. when I pull off plug wire #3 nothing happens put I hear a click/spark when I reattach #3. If #2 or #1 plug wires are removed, the engine falls off a little in RPM and pick back up when each reattached. Engine idles rough when at low idle and smooth at high idle. I haven't had in back in the water yet. Is there something else I should check before doing an in water test? Should I pull and ground the plugs and crank to see if I am getting a good spark in all 4? When I used the spark tester connected in my car ( to test the tool) I got bright frequent flashes from the light. Engine has a 2 year old CDI box.

 

[JKEP44]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Maybe go in the other direction and look at carburetors if its like my 75hp and has multiple. It really sounds like the #3 cylinder isnt getting any fuel. If you pull the plug wire off #3 at idle does it make a difference (you said engine running I assume you meant trying to pass 1/3 throttle). There are transition ports in the top of the carb above the butterfly that start coming into play at right around 1/3 throttle. I dont know, sounds like you are all over the ignition side of it, maybe its in another direction.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Yeh I know I jumped from the fuel to the electrical after confirming good fuel flow to the carbs, but the motor dying with a complete cut out by removing the #4 plug and removing the #3 plug having no affect, got me poking around the electrical side. It is a 2 carb motor with the lower carb servicing the #3 and #4 cylinders. So I suppose I will go with removing and cleaning the lower carb next, or just do both of them.

 

[JKEP44]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

I would do both. Most of the time the top one has to come off to get to the bottom one anyway. Make sure you get to the fuel passages in the top of the carbs and not just the bowls. Do the spark plugs all come out looking the same or are some different colors on the tips (soot black, brown, shiny silver ect)?

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Spark plugs all look the same -shiny no soot. They have been this way since last season when I first got the motor running, which I know is not the way they are supposed to be , but the motor usually starts easily ( with a back fire on the first attempt when cold) and runs fine with power.

 

[JKEP44]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Have you looked inside the spark plug hole at the top of the piston? It sounds like its just a little lean. Is the top of the piston shiny also or is there carbon on it? I would say defiantly clean the carbs. Stall at transition (1/3 throttle), shiny plugs, and backfire on cold start are all indicators of lean low end. All pointing to: transition ports in carbs, low speed jets, and idle air mix in the carb. Ignition could definitely do it as well, but sounds like you have covered that part

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Thanks I will check the piston tops and after cleaning the carbs recheck the idle mix screw ( on top front of carbs) . I don't recollect the low speed jet being adjustable - Tolefson (sp) carbs.

The weird thing is last nigh we tested the motor in the water, did a couple of hole shots and ran perfect. We only ran the engine for about 15 minutes. Then took boat out this morning for fishing and same old crap - die out when going to 1/3 throttle. Last night we were in the lake with 65 degree water and this morning we were in salt water which is about 55 decrees. ????

 

[JKEP44]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

I didn't make it very clear earlier. I meant that the low speed might be slightly clogged, and you are correct they are not adjustable. The real area to make sure of us the top of the carbs where those transfer ports are. A lot of people miss that. There are ports above those little tiny holes by the butterfly that can be accessed from the top.
As far as it running great one day and not the next I can't explain that one.

 

[Frank Acampora]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

I have been reading this post for a while and thinking: I still don't have a good idea but--- Try checking the ground wire from the distributor body to the distributor mount. Also check the wire or wires from distributor to the CD box and terminal strip. ALL these wires move when the distributor advances and it is possible one of them has an intermittent break.

NOW: Carefully check where the CD wires go under the flywheel. This was a weak spot on old Chrysler ignitions because the wires could rise, rubbing the flywheel and shorting out. It is possible that there is only enough vibration at over 1/3 throttle to cause this.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Thanks guys. Got the carbs cleaned didn't see anything unusual. Floats were both a little out of adjustment both high and low, but less than 1/16 out of spec.

Frank, I will run down the wires as suggested. Thanks for all your help in the past, a couple of years ago, on this motor. It was essential.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Well here is where we are. Checked the timing and it is spot on at 32 when throttle wide open, but no spark. See video. It could be that I don't have the plugs fully grounded - would that explain the weak spark. But what is going on when #1 plug won't fire with throttle open?

1979 Chrysler how to set timing - YouTube

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Here is vid of plugs firing. They all fire, but what is up with not getting the #1 plug to fire when doing the static timing?

Is this normal spark? Spark plug fire - YouTube

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Well, thanks to Frank I did find the distributor ground wire, from the dist body to the mount to be loose. Tightened it up. Then with the "cleaned" carbs and the tight ground went out and the motor ran great for 2 trips but went back to the old cut out at less than 1/3 throttle on the 3rd trip.

The only other thing I have noticed is the fuel line bulb does not get hard. I was able to squeeze gas to the carbs ( pulled the hose at the carbs) and it flowed out fine and gas flowed out fine cranking the motor with the hose at the carbs when I was testing the fuel pumps. Squeezing the bulb will not get gas to dump out the carbs, so does that mean the float needles are working or there is a problem with the bulb?

 

[Frank Acampora]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

It could be a problem with either pump. The pumps are in series with the bottom one feeding the top and a malfunction in either can cause a lack of sufficient fuel. However, that still doesn't explain a lack of spark which you are complaining about.

Remember: The fuel pumps are pulling fuel through the line and primer bulb. It will never be as hard running as it is when you squeeze it. As long as it does not get sucked flat, you are getting fuel through it.

The plugs in your second video appear to be firing normally.

AHA! I just reviewed your first video and originally I could not hear what you were saying. You are hearing arcing INSIDE the distributor cap at 32 degrees. The distributor cap has 4 unused terminals which are grounded to the body. If you are too far advanced, the spark will PREFERENTIALLY jump to the ground instead of the correct terminal to #1 plug. SO: remove the dist, cap and look for evidence of spark damage at the grounded terminal. If so, RESET the dist. pulley so the curved line matches the curve of the flywheel at top dead center and the straight line points directly toward the flywheel. Check to be certain that there IS a woodruff key holding the pulley in position.

Double check what you think is 32 degrees. START from scratch and set everything to baseline. (It IS possible to have the rotor set too far advanced yet still be able to set timing to 32 degrees BTDC)

If this is NOT the problem, then you need to clean carbon tracks and/or deposits from the distributor cap. Lastly, look for other reasons the spark is being diverted from the correct terminal. Are the two center cap screws too long? They should NOT protrude through the distributor cap.

 

[Frank Acampora]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Oh, yeah! I forgot: While you are at it, check that TDC as marked on the flywheel is actually TDC. If not check for a broken flywheel key.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Thanks Frank. We replaced the fuel bulb and ran great for 3 days. ( that is why the delayed response) Then crapped out - dead. Now no spark with plugs grounded. I did the TDC check per your video with the screw driver into the #1 cylinder. It matched up with the flywheel mark. Anyway I will look under the cap again. I know the mounting screws aren't too long, since at one time they were and that has been resolved. Can you give me the link to the "no spark" diagnosis so I don't have to pester you. I have the new CDI box - it hums when energized.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Is this a good troubleshooting reference Page 2 - Chrysler outboard ignition troubleshooter for no spark issue?

 

[Nordin]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Yes, go through the troubleshot and I think you will find the issue.
BTW Did not hear so good in your youtube video, but is the BTDC 32 dgr at WOT correct adjusted?
When the carbs are at WOT the timing pointer should point at 32 dgr and when you push at the belt #1 plug should spark.
If not adjust at the timingtowerlink to the distributer.

 

[seattle scott]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Thanks Nordin. When I push the belt with the flywheel at 32 BTDC there is a long "arching" sound, but no pop/spark at the #1 plug, but the motor ran great with a loose ground tightened, for a couple of days, then back to the cut out at 1/3 throttle. Replaced the fuel line bulb and ran great again for a couple of days then died with no spark in all plugs. Started the ignition diagnosis, with the spark tester at 1/2 inch, there is only one spark after cranking for 5 seconds, and that is when the ignition key is released. So swapped out the ignition switch and when cranking there is one spark ( nice 1/2 jump) when the ignition is engaged but nothing after that. So I get one fire when the switch is engaged and with another switch I get one fire when the switch is released. I get 10.5 volts on the blue wire when cranking. I didn't do the white/black wire test yet. I did the gray wire test going to the coil. I didn't know what DVA volts were so I set the meter to 200 DC volts and got zero. ( I now know that DVA is digital voltage adapter which I dont' have) The CD module hums when the switch is "on". One last thing, to get the spark tester hooked up, I used an old spark plug wire form my car that had the boots on both ends, as the tester has a male end, the same as the coil end. I am stumped.

 

[Nordin]

Re: Chrysler 1977 135 dies if more than 1/3 throttle

Okey, I see you have the CDI aftermarket CD box 115-3301 and it will humm when ign. is ON. Your engine has the electronic distributer with a preamp instead of points.

I have had a issue with a 75Hp that I bought. It had no spark so I change the old MagnaPower CD box for a CDI aftermark as yours and I got spark BUT it sparked intermittent and the engione backfired.
Troubleshoted the system and change the preamp in the distributer. After that work perfectly.

Do the white/black wire test and check also check the grounding of the CD unit.

The preamp is expensive so do not buy a new if you are really sure.

Maxrules has the preamp, both OEM F14048-2 and aftermarket 135-4048. OEM is 100 dollar and the aftermarket 151,75 dollar!!!!!!!!!

Think they sale out the OEM.