Most common problems with 4 cyl / 3cyl chrysler outboards

[WinnerCougar74]

Hello,

I would like my 1974 Chrysler outboard to last. It seems like one of the biggest challengs is finding parts. So I would like to plan ahead and start looking for various parts that are known to be needed.

Please post things on the 4 cylinder and 3 cylinder (since they share many things in common) that commonly need to be repaired or replaced. Thanks and maybe this will help other people to make these great old motors last.

 

[topgun3690]

Keep an eye out for a good parts motor.......one that is not running, has a blown PH, etc......can be had pretty cheap. So far I haven't had any problem finding parts for my '78......using ebay, Franz Marine, marineengine.com, MasterTech, boats.net, Crowley, etc. Consumable parts like gaskets, t-stats, impellers and such seem to be readily available.
With a good/complete parts motor on hand you will already have most of the hard to find stuff if you ever need it.

 

[jerryjerry05]

Your part: regular maint. Check/ change gear oil, yearly water pump impeller change, new plugs, keep the fuel tank as full as possible(keeps condensation low, use fuel stabilizer and run the motor out of fuel or drain the carbs over winter, grease the motor on a regular basis.
The others might add things as time goes on.
Don't be afraid to ask questions.
I had a bunch of Force 85's and 125s and they all were great running motors.
The worst that happened to them was I used them in salt water and that eventually ate the mid section and transom clamps and through bolts. Grease and lots of it.

 

[Nordin]

As topgun and jerry says, parts engine is a good ide.
Maintain it regulary, if you do not want to pay much money for ignition parts (I suppose you have the Motorola Magna Power I CD box and a belt driven distributor with a preamp instead of points) buy a used distributor with points.
If the preamp or the CD box fail you can convert the ignition system to a regular auto style system with points and condenser.
Much cheaper than buy a preamp and CDI aftermarket CD box.

 

[WinnerCougar74]

Seems like most people that own these motors say it's hard to kill them. In the last 5 years the biggest expense was a starter. Otherwise I have a box with the following parts in it. Fuel pumps diaphragms, distributor belts, spark plugs, points, water pump parts, impeller, lots of difference gaskets, shifter cotter pins and pins, thermostat, lower end drain plugs, distributor cover, poppet valve, set of reeds, prop nut and cotter pin. Also got a complete very good condition lower end from a 105hp for $200 and complete rebuilt set of carbs for $165. Just typing this all out makes me think I am probably in good shape. It is finally time to go try and wear out this old 1974 135hp with 140-135 psi compression. Just had it out and the only problem it consistently has is it doesn't like to idle for more than 5 or 10 minutes, it starts to foul the plugs easily and once you foul the plugs you are toast on the water. I think one of the most important things you can do is to put a cover on the motor to keep the sun off of it. It just sits there and bakes all the seals in the motor if you don't use a cover. I personally think it is very cool that a 50 year old motor still runs.

 

[WinnerCougar74]

2 new developments, I cleaned the fuel recirculation system and reset the idle mix screws and now it idles very nicely with minimal fouling. Also, when it's warm out while out on the lake moving from spot to spot it starts right up with just a little tap of the ignition switch. So I'm loving this motor now. Biggest problem now is when I tilt the motor up for trailering it dumps fuel into the splash well. Very irritating and a potential fire hazard. It's hard for me to imagine that Chrysler was ok with this from the factory. I am thinking maybe I should use an transom saver and not tilt the motor up so far and maybe this will help. Some say it's hard on the transom to trailer the boat in the full up position.

 

[Nordin]

One simple tips is to put a piece of rag at the bottom cowl just in front of the carbs when tilting the engine up.
It will absorb the fuel, then pull it any when running the engine and then change it every time you tilt it up.
I do not think there was an air silencer at the 4 cylinders as it was at the 3 cylinders that catches the fuel and lead it back to the crank case with a hose in the bottom of it.

 

[topgun3690]

Some say it's hard on the transom to trailer the boat in the full up position.

Best to have engine all the way down when trailering, if possible. If not, support it with a transom saver or similar. With it tilted up and not supported, it puts a lot of fore and aft flexing on the transom.

 

[racerone]

Run fuel out of the carburetors before putting boat on the trailer.----No spillage.-----And empty carburetors stay clean.

 

[WinnerCougar74]

So it sounds like it's a common problem from the factory with this motor. I'll have to experiment with how long it will take to run the motor till the float bowls empty out. I already have a fuel shut off valve so after the boat is load I could shut off the fuel and let it sit and run a little while before pulling it out of the water. Also, I should use a transom saver. I wonder if I can find the 3cyl baffles you are talking about. I guess it would need a one way check valve.

 

[WinnerCougar74]

Last time out it looks like my plugs are still fouling. Very frustrating, Seems unsolvable. 1 turn out on the idle mixture screws, carbs are clean and synced, ignition is right with new points, new coil and timing is right, recir system seems right, compression is between 137-140. Some say they can idle a long time with these motors. It runs good otherwise. I could run this motor forever but this fouling plugs things is a pain. I guess I should just buy boxes of plugs and replace them all the time. It's not really that expensive. One question I have on the recirc system is, I installed blue see thru fuel lines so I could see the fuel moving but I didn't really see much at idle. How do I really know of the recirc system is actually work?

 

[WinnerCougar74]

I just put in NGK BUHX plugs, the ones with the "boost gap", we'll see if they help.

 

[Nordin]

In my opinion 2 strokers do not want to idle for long times.
The bigger engines the harder it is to idle for long times are my opinion.
The advantages with those surface gap plugs are they are easy to clean from fouling.
Just wipe them with a piece of rag.
If you have clean the screens at the recirculation system and the check valves looks good and are flat they suppose to seal as they should.
If you are seeing gas flowing through the hoses it should work as supposed.
I do not know how you should figure out if the flow is enough, maybe some other at this forum would know such as, jiggz, topgun3690, jerryjerry and The force power.
They have much experience in 2 strokers and especially Chrysler/Force engines.
Remember this engine we are dealing with is 50 years old and a carb feed engine from the mid 70.es.
It is not a new computer controlled engine as the 2 strokers from today.

 

[racerone]

????----I used to troll for hrs with 235 HP V-6 Johnson.-----Parts / pieces do not know how big the motor is !!-----Motors in top condition will troll all day long !

 

[jerryjerry05]

Last time out it looks like my plugs are still fouling. Very frustrating, Seems unsolvable. 1 turn out on the idle mixture screws, carbs are clean and synced, ignition is right with new points, new coil and timing is right, recir system seems right, compression is between 137-140. Some say they can idle a long time with these motors. It runs good otherwise. I could run this motor forever but this fouling plugs things is a pain. I guess I should just buy boxes of plugs and replace them all the time. It's not really that expensive. One question I have on the recirc system is, I installed blue see thru fuel lines so I could see the fuel moving but I didn't really see much at idle. How do I really know of the recirc system is actually work?View attachment 402579

Only one way to know if the recirc system is working: take it apart and check the screens and the small nipples for clogs. A welders tip tool to clear the nipples. A can of carb cleaner with the small red tube to flush the nipples.

 

[racerone]

Install better non fouling plugs??

 

[WinnerCougar74]

It's fascinating how many different opinions there are on plugs fouling on 2 stroke outboards. I am from the 70's and remember how tricky it was to get an old 70's carbureted motor to purr. If you did get it purring it wouldn't last. It seems like you where always tinkering especially when the weather would change. Back then maintenance intervals where much closer. Replacing plugs was a very regular thing. Hopefully the "boost gap" NGK's I have in there now will help. Thanks for all of your viewpoints.

 

[racerone]

I have trolled for hours and hours with a 63 Johnson 10 HP at 24:1 mix.----Rebuilt it myself.----Plugs do not foul.-----Find the real issue with your motors I say.

 

[WinnerCougar74]

I must say after many hours of troubleshooting and dragging my but back to the dock I think I'm ready for a simple fix. Just replace or clean the plugs more often. Plus, I am convinced it has something to do with the design of my old 4 cylinder 2 stroke. It does seem like some of the chronic problem got resolved over the years. Is the design of the recirc system on my engine different than the later force motors?

 

[jerryjerry05]

The new is a lot different than some of the older variety.
The old recirc system would just dump the fuel overboard.