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Chrysler 55hp issues

T

TD28

Contributing Member
Hello everyone new here. I got an old 72-73 Chrysler 55 outboard that I'm having some annoying problems out of. Been working on it for a little while now and when I test it out at home it'll start right up and have zero problems but when I get on the water it wants to take 20 plus minutes to start then stumble down and die and when i did get it running I had max speed/ throttle for about 30 seconds then it just started revving up. I can still move forward at maybe 1/8 throttle. it did sit for 4 years but was running like a champ and when I decided to repair it I pulled off the flywheel put in a new keyway cleaned and gapped the points to.020, cleaned the carb and replaced the idle/timing tower since it was broken. all fuel lines are brand new with an inline filter. Gas is fresh and properly mixed and just checked it fired right up and ran max speed in gear no issues out of water with hose hooked up. Any help would be greatly appreciated.
 
Check for spun hub or spinning hub.
Remove the prop, scribe the rubber hub with an awl or magic marker. Then take for a ride and when the problem happens: remove the prop and check the line you made on the hub. If the line moves??then the hub is bad. They can be re-hubbed. Find a prop shop or take to the local marine parts store, most places have access to a shop that does the work.
Google: how to check for a spun hub on a propeller video:
 
Took the prop off and yeah I'm sure that the hub was spun. Fortunately I had a spare prop but this ones also old so I'll rehub it. I didn't see a washer or anything behind the prop just had the shaft the prop the pin and cone. For the issue with the carb any advice on tuning it?. I went by what the manual shows but maybe I'm doing it wrong.
 

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https://forums.iboats.com/ This will lead you to another repair forum. It has a section for help and tips and some procedures for repairs on Force/ Chrysler motors.
The first 5 posts in the Force/ Chrysler section has tip and procedures.
You can always Google any specific repairs you need. Just ask for videos??
 
Thank you for the info. Do you happen to know the prop hub part number? The ones I see on Google are square looking and the hub slot in the prop is circular. I called my local marine shop and they didn't know.
 
The square hubs are for newer style props. The hub is easily replaced with the new style.
The older needs a 20Ton press to push the hub back into place.
Google: "who rehubs older style propellers for boats" add in your location and the local places should pop up??
Most marine sales/repair places will have access to a shop who fixes them.
 
So i can use the square hubs in my old prop? I have access to a press my local shops said they elude but did give me the number to a boat junkyard that isn't to far out.
 
No the square won't fit.
Any kind of marine sales or repair shops? Take the prop to them and they can send it out.
Google: boat propeller rehub, repair ( insert your state)
In Maryland there's a company called Millers Island propeller sales.
410) 477-4500
https://millersislandprop.com/ I have used their services since 1986(when I lived in Md.)
Contact them about buying a hub.
 
Gave them a call and they had a couple so I bought enough to do my spare prop and my one on the motor when it spins.
Thank you for their info.
 
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Thanks for the tip especially about the press. I got it out easily with just a hammer and socket but I'll take it to work and press it right
 
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I got it back moving but it bogged down and died on me at wot after about half a mile. I've tried every adjustment even rebuilt the fuel pump and I cannot get it to properly idle at all. To even move i had to have the neutral switch on with throttle up and had to be fast when I took it out of neutral or it'd die. Mixture screw is 1.5 turns out and the tower idle screw is slightly in. Also adjusted the float so it's level when upside down.
 
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Do a starting fluid test.
Start motor, (even high idle is ok) spray SF around the intake side of the motor.
This includes under the coils and pack anywhere on the stbd. side.
If spraying the SF makes it bog, cough, stutter or die, then it's sucking air somewhere.
Oh yea, the base of the carb and anywhere it can draw air.
Post the results.
Under the fuel pump is a port cover, there's 2 on your motor the gaskets can be blown/sucked out and allow air to be sucked in.
 
I tested like you said no issue. Now she's eating spark plugs in bottom cylinder. First one is after 10 mins brand new plug second one is old plug. I've adjusted the carb a lot I have gone 1 and a half to 2 and a half turns on mixture im thinking maybe I have the tower screw in too far advancing the timing? Last time I was wide open riding when the plug gave out. Any ideas? I've scoped the cylinders and no damage internal. Also plug 1 is perfectly fine.
 

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First question: are they the right plugs? I have never seen that before. That's extreme heat.
That kind of heat comes from the wrong jet/ jets, sucking air someplace.
One thing for sure: you'll melt the top of the piston (1974, Triumph Motorcycle, just rebuilt, bored out 100k and didn't re-jet the carb and check for air leaks, burned a hole in top of the piston)
I'd redo the starting fluid test again. Paying close attention to the port cover for the fuel pump.
Maybe use surface gap plugs UL18V for testing.
 
Does spark now jump a gap of 5/16" on both cylinders ?----Installed a new water pump impeller ?-----Checked reed valves?
 
Ngk br6hs i believe. Ill redo the test. I redid the impeller years back and it does have good water flow currently that's why I thought maybe I had my ignition advanced too far since the tower idle screw is around 3/4 in. Haven't checked the reeds yet.
 
Spark is tested using a tool made for the procedure.----Store bought or home made.----Sparkplugs are NOT used for this test.----Does spark jump a gap of 5/16" , yes or no ?
 
Ill have to either make a tool or get one to test the jump distance id guess harbor freight has one or I could make one with some wood nails and wire right? It iss odd that its only the bottom cylinder burning plugs like that tops fine both times it has happened.
 
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Some simple testing on your part will find the issue.----Cardboard / plywood / nails / wire / glue and you make a test device.---Post picture of burned plug.
 
I have had a simple spark testing tool ( 4 leads at a time ) for 50 years or more.----Compression tester and spark tester are VITAL in trouble shooting.----Spark may jump a gap on a sparkplug laying on the block.----That does not mean spark will jump in the cylinder with air pressure at 120 PSI.
 
I've just been testing spark by plug on the block. Compression is at 125 so all good there. hopefully parts store has one if not i just looked up a video on making one with an old plug wire and the method you described earlier. I get off work in an hour so i'll test it before getting some sleep and report back.
 
sounds similar to my issue, i just tested my trigger and its shot. i can start in driveway and anytime when engine is cold. once it warms up, im losing power in one of the cylinders or spark. if i idle it will shut off and then forever to get it started, mine was a domino effect. had bad thermostat, fuse was blown and thermoswitch melted, not sure what caused what to what. but i started checking wires and found two almost melted on the block and then tested trigger was 30 ohms vs 700-1000. will get part saturday but on vaca. google trigger and see if it matches your issues.. ai is legit. ha
 
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