Sick 1973 55hp Chrysler

[7355hpchry]

Just got this motor. It sat for an unknown amount of time in the hellish Arizona Desert. It will start(not eaisly but it starts) and idle but when I put it in gear, it won't rev above 1500RPM. I give it gas and it just dies. Went through
Awakening Procedure.

It will rev up fine in neutral when I manually work the carb butterfly. No power, no rev, in gear.

I went through the very simple single carb, it seems to be ok, what next?????

 

[pnwboat]

Re: Sick 1973 55hp Chrysler

Have you checked the plugs? Check compression and spark. Compression on a used motor should be in the 100 - 125 pound neighborhood and within 10% of each other. Or with the engine running at an idle, pull one spark plug wire off at a time and see if it makes a difference. If no difference on a particular cylinder, then that cylinder is not working properly. Could be spark or low compression.

 

[steelespike]

Re: Sick 1973 55hp Chrysler

Be sure it is running on all cylinders.Be very careful don't do any ignition trouble shooting without a service manual.careless trouble shooting can damage the ignition system.The magna power ignition is very sensitive to careless handling.Does it respond to the choke when struggling?
Does squeezing primer bulb help?You could CAREFULLY squirt fuel mix into the carb.If it resaponds to primer bulb suspect the pump or fuel lines.If it responds to choke or fuel squirt suspect gunk in carb passages or jets.

 

[Frank Acampora]

Re: Sick 1973 55hp Chrysler

Definitely check the fuel pump diaphragm It may just not be delivering enough fuel. It takes almost nothing to accelerate in neutral but fuel requirements go way up in gear.

Also check the six block bolts--the bolts that hold the two block halves together and also support the center bearing. 9/16 heads, not the small 1/4 -20 with 7/16 head flange bolts. With these engines, sometimes The block bolts loosen a bit and the two halves will spread just enough to leak between crankcases, even with the flange bolts tight. the engine will run fine up to about 1500 then run flat as if overcarbureted. Carb will be ok, fuel pump will be ok, tank and fuel lines will be clear, and you will scratch your head wondering.

And it doesn't take much--1/8 turn or less loose on the bolts will do it.

 

[7355hpchry]

Re: Sick 1973 55hp Chrysler

Well, I found the problem. The #1 spark plug wire was rubbing against the flywheel. It started touching at about 1/4 throttle as the stator plate rotated to advance the timing. This did not happen when I was working the throttle at the carb.

So now my next problem, finding a coil/plug wire set up. I have it heavily taped right now, and the engine is running great. Now I fear, moisture will still find a way through the tape and bugger up the exposed steel core of the plug wire.

My Clymer manual suggests the plug wire can be removed from the coil. I don't see any way in hell to get that wire out of the coil. I looks to me like the plug wire was molded into the plastic housing of the coil.

Anyone know where I might find the parts I need? Also what ignition system do I have? Under the flywheel is just 2(two) sets of points, condensers and coils. There is no alternator/generator even though my motor is electric start.

 

[eurolarva]

Re: Sick 1973 55hp Chrysler

You can try Mercury with 85-818076A2 part number. Price is around $120. There were two types of coils. One had removabe wires and the one you have does not have removable wires. Yours should be the standard ignition versus the Magnapower ignition.

 

[Frank Acampora]

Re: Sick 1973 55hp Chrysler

That's a sweet little engine. I think you will find that if it is running properly, it will beat any brand 50-55 of its age. Not bad for old-school technology. I probably have at least a couple of thousand hours on my 1967 55.


What you have is magneto ignition, electric start, without an alternator. Thus: after a day of use for something like water skiing where you stop and start the engine multiple times, you must re-charge the battery. It is not a simple fix to retrofit to an alternator so you are best off leaving it as it is. BUT--the battery is only used for starting, so while running, it will not discharge.---I took the same engine of an earlier year on an on-water trip to Canada from New York. Four days up, four days back. No battery problems, although I did bring a trickle charger and charged it once overnight. And even if the battery is dead, that engine is easy to rope start. Just turn on the key, prime the carb, wrap the rope about three times around the flywheel collar, and yank.

Rather than buying an expensive new magneto coil, Just remove the tape, coat the wire with black silicone RTV and then re-tape. It will work just fine as long as the wire is not broken. OR--Remove the boot, slip on a couple of layers of heat shrink tubing and replace the plug boot. (that's not as easy as it sounds.)

If you absolutely must spend your money, I have a couple of used coils for 100 bucks each LOL--just kidding I need them for my 55. But seriously, go over to The Chrysler Crew and see if you can't buy a used one in the classified section. Any one off a 35 (of this series, not the 35 of the 20,25,35 series engines), 45, 55 will do. They were all the same block and ignition system. Should be quite a bit cheaper than Merc.

Oh, yeah! Forgot to mention: Points are set to .020 and I think plugs are gapped at .035