50 Hp Force 507X5A

[msstring]

Runs great at full throttle but won't idle or troll after it warms up. Seems to run ok cold.

 

[msstring]

I'm not sure if it is a fuel issue or electrical. It seemed to get better when I was pumping the bulb but then it got worse again so no conclusion. If it is the pump diaphragm would it be likely to only show up at low RPM?

 

[roscoe]

A hole in the diaphragm will dump fuel into the crankcase, cause a flooded condition.
So yes, this could be your problem.

Fuel pump kit is a maintenance item, should be done every 10 years or so.

 

[jerryjerry05]

Do a compression test.

Can of starting fluid.
Start the motor, spray the SF around the intake side.
If that makes it cough, stutter, run better even stall??
Then it's sucking air someplace.

Reset the air screw on the carb.

Top posts have great info, read the first 4

 

[msstring]

Thanks everyone for the feedback. Hopefully Saturday I will get some time to do some testing. In the meantime, tonight I pulled the plugs and will try to post pictures. The one I am holding is the top one and the one one the ratchet is the bottom one. I also see the one coil is really cracked. Is that normal? Or should that be replaced? Doesn't seem normal.

If I need to replace the coil(s), does anyone know where i can find the part # or where to get them? I tried the iBoats store but the coils are not listed unless I don't know where to look, which could be. http://ww2.iboats.com/Alternator-An...258194--session_id.819793152--view_id.1687766

 

[roscoe]

Coil from Mercury is part number
[h=1]Mercury-Mercruiser 300-803830T $185[/h]
Original part number was F380475

No aftermarket coils available.


Thats why my motor got scrapped.
Tried to part it out, but no one was buying.

 

[Nordin]

As you engine has battery ignition system the problem with running bad when warm can be bad coil which would leak current when getting warm.
Yes your cracket coil can be the issue but it can also be bad condensers which also can leak when getting warm.

I would check if the spark disappear at one cylinder and then swap the coils and check if it follows.
If not swap the condensers and check.

 

[jerryjerry05]

If the coils making spark?
No need to replace.
The stuff you see on tv it's a black rubber that coats a screen door and keeps the boat afloat.
Remove the coils and double coat with the sealer.

Run after dark and check for spark jumping.
The coil wires can be coated and shrink wrapped to stop the jump.

 

[msstring]

If the coils making spark?
No need to replace.
The stuff you see on tv it's a black rubber that coats a screen door and keeps the boat afloat.
Remove the coils and double coat with the sealer.

Run after dark and check for spark jumping.
The coil wires can be coated and shrink wrapped to stop the jump.

Thanks Jerry, can you give me any more to go on for the black stuff... I don't watch TV, are we talking a Grilla tape or something like that? It is Ammozon day you know... Thanks again for the tip.

 

[msstring]

I think I have narrowed the issue to electrical. I have added some video showing the motor running to the same folder linked before. On the one that is darker (lights out) at about 50 seconds in I start running the timing light and you can see the light go out and motor runs much slower and rough. By this time the motor had been running for at least 30 minutes. So, that seems to me like that plug is not getting spark. Then I switched the coils which is the other video. Dinner bell rang before it ran long enough to start missing but my imagination said it was running smoother. I'll test more another day. Let me know if the video or any of this makes sense.

 

[jerryjerry05]

If it runs for 30 min then dies??
I'd guess the coil is breaking down as it heats up.
Start the motor and let it get hot.
Then touch the coils and see if one is hotter than the other?

Is it me or was there a knock in the motor?

Another test, temp gun, run the motor and when it dies take the temp of the whole motor.
Looking for hot spots. Might be overheating?

Franz Marine should have the coils?
Used coils ??? stay away.

 

[msstring]

If it runs for 30 min then dies??
I'd guess the coil is breaking down as it heats up.
Start the motor and let it get hot.
Then touch the coils and see if one is hotter than the other?

Is it me or was there a knock in the motor?

Another test, temp gun, run the motor and when it dies take the temp of the whole motor.
Looking for hot spots. Might be overheating?

Franz Marine should have the coils?
Used coils ??? stay away.

Thanks, I was worried about that knock too, I didn't know if that was normal or actually a knock. Coils both get hot to the touch, I can't hold my fingers on them very long. I'll get a temp. next time and see if they differ between them.

 

[Nordin]

That engine does not sound healthy.
Sounds like a bad piston pin or bad upper crank ball bearing.

I have seen Chrysler 45/55Hp (same engine as yours) with a crack in the ball bearing (outer ring of the bearing).
If the balls are worn they usually whistle.

 

[msstring]

That engine does not sound healthy.
Sounds like a bad piston pin or bad upper crank ball bearing.

I have seen Chrysler 45/55Hp (same engine as yours) with a crack in the ball bearing (outer ring of the bearing).
If the balls are worn they usually whistle.

How horrible is it to change bearings?

 

[msstring]

Engine knock, listen to the motor in the linked video. JerryJerry05 and Nordin already told me the motor doesn't sound good. Thanks for that bit of not so great news guys!!! So now I'm looking for someone to tell it sounds just fine! Or that there is some easy fix!
No, really I do appreciate the support even though it's not what I want to hear.

with the motor off I grabbed the flywheel on two sides and can get a little tick noise as I twist it back and forth. Could it be possible that I have a loose flywheel causing the knock! Or is that just wishful thinking? I'll pull the flywheel another day. I also get a more noticeable tick when turning back and forth between compression strokes. I'm guessing that is not a good sign either.

Is it feasible to rebuild this motor? Or put new bearings in it?

Could really use a geine to give me some good news here!!!

 

[Nordin]

From what your are describing of the tick noise when turning the flkywheel back and forth you have an issue in a piston or a connecting rod.

If the flywheel is loose it should share the flywheel key soo I do not believe in that.

You have to pull the engine appart to investigate and to see if it is worth a rebuild.
If you are in the US I believe there are a lot of these Chrysler/Force 45/50/55Hp for sale cheap and use your engine as donator or put one engine together from two.

But you have to investigate first, hard to say from only listen to the engine if it is worth a rebulid or what is wronge with it.

 

[jerryjerry05]

Actually pretty easy to rebuild.
The parts are easy too find.

Can you push on the flywheel and move it?

I've found that kind of knock is a connecting rod problem.
It might be slapping in the piston or the bearings are bad.

You can take the carb and reeds off and try moving the rod at the crank.
Or remove the head and try moving the piston, should have a little side to side.

Check the timing before you start a tear down.

Can of starting fluid, start motor, spray around the intake side and if it makes the motor run better, worse
then it's sucking air. That can cause a knock.

 

[msstring]

I added 3 more videos to the album showing me making the knock by moving the flywheel. One turning back and forth, another twisting up and down and a third pulling and pushing back and forth. The video really amplifies it from what I heard. Seems like the play is coming in the top bearing. I read an article on here about someone changing the top bearing by pulling the flywheel. That didn't sound terrible. Do you think it would be worth trying? Oh, is that still more wishful thinking...

I did try the starting fluid and didn't notice any difference at all in the way it ran.

 

[msstring]

Coil from Mercury is part number
[h=1]Mercury-Mercruiser 300-803830T $185[/h]
Original part number was F380475

No aftermarket coils available.


Thats why my motor got scrapped.
Tried to part it out, but no one was buying.

So, is your old motor still around?

 

[jerryjerry05]

Changing the top bearing is a B&^^$.
It's been pressed on and trying to remove it with out a press and torch??

Not sure where your located but the mid-west is loaded with boat salvage yards and used Chryslers.
Google marine salvage, Outboard salvage etc.