1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

[Evinrude_NooB]

I bought a '87 Bayliner with a Force 50 (Model 507X7B). What is the difference between this model and 507X87B? Both are 50 HP.

Not knowing 'anything' about these engines, I did the best I could to check it out. I put the lower unit in the tub of water, started it, and water was coming out of the pee hole. I never put it in gear while on dry land. I took it to a local lake to test drive it and that's when problems started.

After about 5 minutes of running it, smoke was coming out of it and I smelled cooked paint. I shut down the engine and opened the cowl. It was HOT and smokey. I let it cool for an hour and tried starting it, no good.

Finally trolled it back to launch and took it home.

I checked out the engine, and found the head gasket was blown. Also found out that no water was getting to the head to cool the engine. The thermostat was shot, thermo sensor is probably also shot. Spark plug is potentially gapped incorrectly. It was gapped a bit above 0.040 and I found that it should be gapped 0.030.

Engine isn't seized and the piston and cylinder 'seems' ok. Spark plug wire melted on one side.

Could anyone suggest what I need to check and fix to get this engine operational again?

I have taken the head/cover off and removed the following:

* Head gasket
* Thermostat
* Thermo sensor

I will remove the lower unit and check/replace the water pump/impeller as I'm sure that is shot because no water was coming up to the head. I know because I found some kind of insect nest there.

I noticed a large screw on the top of the engine near the thermostat. This suggests that I could install a tube and connect that and run it out so I can check to see if water is circulating up the head. Is that advisable?

What a nightmare.

 

[jerryjerry05]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

The difference between the models could be the year or the type of screws holding it together??
Usually a small thing,maybe the series??
The screw on the top of the head is for a temp guage sending unit or a tell/tale.YES PUT ONE IN!!!
Bugs just love getting up inside the motor to build nests.

Pics of the cylinders?
You can remove the side panels/fuel pump,and see if the pistons have damage.
You mix the gas and oil right?50-1

If eveything checks out replace the impeller,head gasket.
The thermostat test it in hot water or replace it.
Test the overheat system. The sender on the motor,key on,ground out the sensor.
It should make the buzzer under the dash sound off.Bayliner used a small black buzzer under the dash.
Sensors don't usually go bad unless someone messes with them.
Test the buzzer.

Plug gap,most people think the plugs are pre gapped and just put them in.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I replaced the head gasket the other day. I pulled off the lower unit to check the water pump and impeller and it was fine.

One strange thing I noticed when putting back the lower unit. It took me several attempts to get the lower unit back on because I could not for the life of me get the shift linkage threaded on correctly. Each time I pull the lower unit out for a new attempt, I noticed oil sitting in the lower unit. It was green so I think it's gas oil. I could not find out where it was coming from. Is it comming from the power head where the shaft connects?

I am going to take your advice and install the tell tail. Do I need to drill a hole somewhere to run the hose down? That set screw on the top isn't comming off easily. I put some penetrating oil on it and left it sitting. Hopefully it'll come off today.

I boiled the thermostat and confirmed it's shot. Will have to buy a new one.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

Having replaced the head gasket and checked the water pump. I decided to try starting the motor today. It did not start. It did backfire and plashed water all over the place several times.

I pulled the plugs and check for spark and there was spark. There as also gas evident on the plugs. Not sure where to go next. I'll have to get a compression tester and check for compression next. Any suggestions would be a big help. My next thought are the rings and it is something I don't want to do. The reason I'm thinking of the rings is that it seems I'm able to turn the motor too easily by hand at the flywheel. I've replaced a ring before on a much smaller single cylinder engine and it was not fun. If it's not the rings, I'm not sure what else it could be.

To answer Jerry's other questions:

Gas was mixed 50:1.
I grounded the orange wire and key-on to see if the buzzer works. It didn't go off. Maybe someone disconnected the buzzer. I don't know yet but I'll have to check.

 

[jerryjerry05]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

Make sur ethe buzzer works and the system is functioning.
Back fire?? Maybe the plug wires were reversed??

Yea drill a hole and try to find a gromet of some kind.
Granger has a parts catalog of trillions of do-dads and do-hickeys and good stuff.
Installing the tell tale since the thermo is out you might need a bit of heat to remove the plug.
Then drill a hole the size of the hose on the stbd. side so you can see it from the drivers seat.

These things are easy to rebuild.

Post your comp results.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

This morning I borrowed a compression tester from my neighbor. I ordered mine and it takes 7-10 days for it to come, uggh.

Anyways, did the compression test 2x, just to verify consistent results:

#1 cylinder - 50 psi
#2 cylinder - 45 psi.

I have to say these results are not good at all. From reading other posts, I should be getting above 100 psi, right?

Am I correct in saying that either the rings or cylinders are bad? In either case, I need to pull the head off? I'm willing to replace the rings if they're bad, but I don't believe I will go further than that. How difficult would it be for a novice like me to just replace the rings, if they're bad? I've worked on single cylinder engines before and I have to admit that it wasn't too fun.

Thanks for any insight anyone can provide.

 

[jerryjerry05]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I'd try again on the test.
Probably a bad tester or it was done wrong???

Remove both plugs.
Advance the throttle.
Install tester,jump solenoid,don't use key.
Let it turn over, till the guage stops going up.

One at 45 the other at 50.Not right.J

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

Ok.

I've finally jump the solenoid and ran the compression tests.

The results were even worse.

Both cylinders reported under 50 psi. I tried with two marine batteries and when they didn't provide any better results, I pulled up my car and jumped using the car battery with car engine running. Compression was under 50 psi for both cylinders.

Here's the weird part. I also run tests using the pull cord. And the compression numbers were better at 62 psi for both cylinders. My thinking on the 62 psi was that I could not pull any harder. I decided to put the plugs back in and tried pull starting the motor. It did not start but the lower exhaust did 'POP' several times.

Don't know what to take of all this, but it is still broken.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

This is what it sounds like after I replaced the Head Gasket and try starting it.

 

[jerryjerry05]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

You get a different guage?
Getting spark?
Manual.
http://rapidshare.com/files/453372554/force35-150.pdf

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

Still waiting for my gauge. Hopefully it's coming Friday, but might not until next Wednesday.

Getting great spark.

Thank you so much for the manual.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I got the new compression tester today, early.

Ran out after changing out of work clothes for a quick test.

With the new tester, I got 65# from #1 and 62# from #2. Not much different than when I was manually pulling it. I'm a bit dishearten because that's about 1/2 of what the manual says I should be getting.

What do you think?

Than you.

 

[catfishcarl99]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

well the compression doesnt sound good. im not really experienced in motor internals. ill let the mechs take care of that. but heres a vid of my pizzer i installed on my 50. mines a 507y9b and very simmilar to yours. top cowls are different but many other things are the same.
my project was about $12 to complete. working great still. no over heating troubles at all. posts are in this thread link

http://forums.iboats.com/showthread.php?t=562283&p=3878721#post3878721

added an idiot light to my buzzer to. thanks to jerry for the new buzzer and confirming my light idea would work.


http://forums.iboats.com/showthread.php?t=553093

i too cooked the paint one time and blew my head gasket. but after i put a new one on i got from here it fired right back up. never had any trouble with overheating since. change impellor ever couple years since. thats why i added the tell tale and light along with buzzer. i went from 1 sign to 3.

 

[catfishcarl99]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

 

[Nordin]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

That indicate the both cyl. has damage. Hopefully only rings and pistons. Maybee you do not need to rebore.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I was afraid of that.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I guess I'm looking for a 'new' used outboard, http://forums.iboats.com/showthread.php?t=577363&p=3966964#post3966964.

Do you guys think a running used Force 50 is worth $400? I've found a 1974 Evinrude 85 HP for $450.

 

[Nordin]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

I would put my money on the Force 50. The Rude is 38 years old and the Force might be at least 10 years younger (the 45Hp Chrysler were rated 50Hp when US Marine bought Chrysler and named it Force and that was in 1985). But everything depends on how well it been maintained.
You have one spare engine for parts and if you are a little mec skilled, restore the bad one and then you know all about the Force.

Now I am a Chrysler/Force and even Merc fan and I have never liked the OMC:s so thats why I suggest the Force.

 

[catfishcarl99]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

ya if its just rings them are decent motors. other than my screw ups (shorted a wire and fried my cdi) and had a bad wire arking, mines been a great lil motor. mines an 89. there fairly easy to work on and parst can be had on ebay pretty regularly.

 

[Evinrude_NooB]

Re: 1987 Chrysler Force 50 (507X7B) - overheated/dead & need to fix

If I was sure it was JUST rings, I'd replace it. But I'm afraid that after taking it apart, I'd have to replace rings, pistons, valves, and who knows what. After just pricing pistons/rings and the all the gaskets, the price was getting to be more than 1/2 the price of a used motor. I figure that's the safer bet than tearing everything out and rebuilding. If I could get another Force 50, then I would keep mine for a spare parts cache. Ideally, the new motor would never break down and I would not need parts. I'm being way too optimistic though.