Chrysler 55hp woes and 50hp revival

[dunnbeetle]

Hi guys,

Just picked up my first boat, a 1970's Crestliner with a 55hp Chrysler engine. I got the boat very cheap, so was expecting issues with the outboard. Long story short, I got it home and checked the compression - One cylinder was at 110 and the other one was at 70. Checked with throttle wide open and both plugs out, multiple times. I then also noticed that the lower unit had been cracked and jb-welded by someone and is still leaking.

I started looking at other outboards and came across a listing on craigslist - "50 horse Chrysler outboard - FREE". The ad describe the motor as one that has sat in the shed for 20 - 30 years. So I was like, well I'll go check it out and maybe I can use it for parts. I get to the guys house and tell him about my situation and that i'm just looking to see if there is anything I can salvage off of the one I'm picking up. The guy replies "well this has 0 hours on it". And I ask if it was rebuilt, he says no and that he just never used it and has been sitting in his shed. The outboard looks fairly clean and the prop has almost no wear.

So I get the motor home and take the cover off, there is some corrosion/rust on some things and I cant turn the flywheel(only tried gently by hand). So right now I have it sitting spark plug side up and I have sprayed some PB Blaster into each cylinder and am going to let it sit a few days.

My question to you guys is, will any of the parts off of my 55hp fit on this 50hp? If this 50 horse has good compression, I plan on going through the water pump/carbs/fuel pump/lower unit fluid. Just wanted to know if there is anything I could use from the 55hp if something is rusted/frozen up. Maybe even the starter?
The 55hp is hooked up to my boat with the controls, the 50hp came with control wires but no control box, am I going to have an issue with that?

50hp - 1983 - serial 507h3d
55hp - I will have to check but I believe it is a 1972 or 1973

I haven't dug into this too much yet and I really know nothing about boat motors, but I have rebuilt car engines in the past. I have done quite a bit of searching and have been able to find parts pretty easily, but there is not a lot of info on the interchangeability of the 2 engines, and really not a lot of info on the 50 horse at all. Any help would be greatly appreciated.

Thanks.

 

[Frank Acampora]

You should be able to swap almost everything, including control box and cables.

 

[dunnbeetle]

You should be able to swap almost everything, including control box and cables.

I've been reading on this forum quite a bit the last few days and I've seen your name A LOT...was really hoping you would chime in here. Thanks a ton!

 

[dunnbeetle]

So a little update on this...

After sitting with lubricant in the cylinders a few days, I was able to turn the flywheel and break it loose. After it broke loose I was able to spin it fairly simple by hand.

Anyway, got the old motor off and the new one mounted, this was fun to do by myself. It was pretty heavy but I was able to do it. I just wanted to get it set up because I don't have a stand where I can work on it or anything. Got it hooked up to the control and tried to turn it over with the compression tester in, just clicked...So the starter looked pretty corroded and since I had another one in the other engine I just swapped them. After that it turned over very nicely.

125 - 130 PSI on both cylinders!

Now I plan on swapping almost everything from the other engine except the water impeller, which I plan to purchase a new one.

My next question is: What else do you guys recommend other than greasing/lubing the lower end? I know I will probably need to tune the carbs.....maybe I have to mess with timing?

Thanks again!

 

[Ahill11]

Not to be a **** and get off the topic but it wont let me start a forum and all forms I look at are from 2014. but

I recently got a boat off of a guy. 16ft maxum 198x and it has a force 50hp motor. I cannot get it to start,
Story: he supposedly had it heat up last year (it charred spark plug cap). and he rode it in fine but it wouldn't start, so he out it away for the year.

I got it the other day, new plugs, battery, I have spark, new fuel (its getting to card) it turns over fine and has good compression however it wont start, I will get a backfire every once in a while. I have tried a shot of ether every couple turns but nothing. what could be the problem? can any PM if they can help and we don't need to blow up this thread.

I was thinking maybe it was flooding out? any help please.

Thanks

 

[dunnbeetle]

^^If you have good spark/compression/and are getting fuel it could be a timing issue. Like I said I'm no outboard expert, but that usually goes for any kind of engine. Maybe carbs, because I know nothing about them...Hopefully someone else can chime in for ya.

Another question: What kind of water impeller should I buy? From looking online, the older ones have more splines, would these fit on the newer motors? Also should I buy an entire kit, or just the impeller/backplate/seal? I have not tore either lower unit off yet.

 

[Frank Acampora]

There were two styles of impellers made: six vane and ten vane. The ten vane is the older style. Both styles fit on the drive shaft. In fact, because of more open area between the vanes the six vane should pump a little more water. By carbs, you do mean the carbs off both engines, don't you? There was a twin carb 55 made and nothing is swappable with the single carb engines.

At any rate, take both carbs apart and do a complete clean-out. Then use whichever one looks better. If the engine has points and magneto ignition or points and battery ignition, remove the flywheel. Clean and set both sets of points to .020

 

[Frank Acampora]

Ahill: Perhaps the moderators will help you to post a new thread--God knows that there have been more problems with the forums since the new format was started. In the meantime, if it has spark and is getting fuel but backfiring, first check the timing at wide open throttle. It should be 30 degrees before top dead center. Then, just because it does have spark does not mean the battery ignition or magneto ignition is working properly. Pull the flywheel and clean and check the points. set to .020 open.

 

[dunnbeetle]

There were two styles of impellers made: six vane and ten vane. The ten vane is the older style. Both styles fit on the drive shaft. In fact, because of more open area between the vanes the six vane should pump a little more water. By carbs, you do mean the carbs off both engines, don't you? There was a twin carb 55 made and nothing is swappable with the single carb engines.

At any rate, take both carbs apart and do a complete clean-out. Then use whichever one looks better. If the engine has points and magneto ignition or points and battery ignition, remove the flywheel. Clean and set both sets of points to .020

I think they are both single carb, and from the outside the one on the 55hp looks almost new so I will probably swap that over.

As far as the ignition system goes.....one is the magneto system(55hp) and the other one has like coil packs(50hp)....I'm assuming I should be able to swap everything over from the 55hp to the 50hp but let me know if i'm wrong. the 55hp has recently been gone through: has a new wire harness, new plug wires, and is not corroded like a lot of the stuff on the 50hp.

Thanks.

 

[Frank Acampora]

Yes, you should be able to swap over the complete ignition system. You must re-wire the switch though. Magneto ignition runs really well with relatively few problems BUT the points and battery ignition has an alternator to charge the battery and the magneto ignition does not.

IfIf you want to see a little points and battery 50 running go to youtube and look up Frank Acampora videos. Search for Mini boat with Chrysler or mini boat with raise transom--something like that. There are about three videos with that 50 and all have different covers-50.55, and (I think) 60

even with a weak battery it turns over and starts first turn--good little engine and it only weighs 160 pounds--lightest 50 ever made.

 

[dunnbeetle]

By rewire the switch, do you mean the plate of like 10 wires that is mounted to the powerhead? If so, that should not be a problem. I will probably be taking the newer wire harness and all accessories off of the 55 anyway.

Kinda sucks that i will be losing the charging, but I can buy an aftermarket one later.

I had actually already checked out your videos on youtube....stumbled across them while looking up videos on the engine and recognized the name. That little boat looks scary, but fun at the same time. Hopefully I can get mine going within the next couple weeks here.

 

[Frank Acampora]

No, I mean the ignition switch on the dashboard or control box. Wiring at the engine terminal board stays the same for ALL Chrysler engines .

The ignition switch has six terminals marked "B", "I", "S"< "M", "M", and the "C" is in the center. Magneto ignition engines use the two M terminals and blue and white wires to stop. At the engine, the blue and white wires are each connected to one of the brown wires coming out from under the flywheel. Turning the key to off shorts the points together, stopping the engine.

Battery and points use the blue wire on the "I" terminal to supply power to the points and coil. Turning off the switch stops this 12 volt power and stops the engine. The two "M" terminals are not used.

The carrier plate and cam for the points is the same on all engines SO if you need the new wiring you can still mount the alternator and coils and get a charge. Wiring is slightly different but take a photo before working and with this as a reference it will be easy.

 

[dunnbeetle]

Wow, yeah that could have been bad if I would have just wired it up....thanks. I may look into leaving the alternator and coils, but i think one of the coils is cracked anyway. I wont have any time to work on this until next week, but I just ordered the impeller and some other parts. Pretty excited about working on it as it's my first time doing anything on a outboard.

Thanks again!