Is my motor shot? UPDATE!!!!! TEST RUN

[88 Bayliner Force 50]

Hello guys. I was driving our boat today on lake jordan. My motor started to lose power at full throttle and started smoking really bad. There is a burnt smell to it even now 3 hours later. I thoght the water impeller went bad so I pulled the lower unit to take a look at it. The impeller looks fine. I did some adjustments on the carb this morning with the idle mixture screw to keep the boat from stalling at a low idle. Could this have caused my motor trouble? Maybe I ran it too lean. The boat ran and idled great for about 2 hours before this happened. I looked at the area around the spark plugs and the paint loooks a little discolored. The "us marine" id plated melted off the cover. What do I do from here. Does the motor need rebuilding? How can I tell if the head is bad?

 

[tiller7104]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

I am going to put in my 2 cents but I am sure that Roscoe and company will give you a more definative answer. First your fuel mixture screw really is not what you want to adjust for rough or low idle it is what it is called "Fuel mixture"! I have made the very same mistake! To me it does sound as if you ran the engine to lean. I know what I would do, I am not sure of your abilities, First I would look at the plugs and see what color they are. Will the engine turn over by hand with the plugs out and if so how does it sound? I would pull the head and look at the cylinder bore. Look for scores that would go the lenth of the bore. Chances are you did some damage if your head is discolored. The other guys on this board I am sure can shed more light and give you more info but off the top of my head that is what it sounds like to me. Sorry

 

[eurolarva]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Get a compression tester and test the compression. Maybe you got lucky. Also describe what the tips of your spark plugs look like. Where do you have the mixture adjustment set right now from fully seated?. When motor overheats the metals expand causing the pistons to become to big to move in the cylinder. This is what shuts the motor down. Typically after a couple of hours the motor will cool down and the motor should crank and maybe even start. Compression testers cost about 30 bucks from a auto parts store or sears.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

OK. I HAVE PULLED THE SPARK PLUGS AND THEY LOOK A LITTLE SMOKEY ON THE TIPS AND A LITTLE OILY AROUND THE THREADS. THE MOTOR DOES TURN OVER WITH THE SPARK PLUGS OUT. IT STILL HAD THAT BURNT SMELL TO IT TODAY WHEN I TOOK THE ENGINE COVER OFF. I AM GOING TO BUY A COMPRESSION TESTER NOW AND CHECK THE COMPRESSION. I CAN TURN THE FLYWHEEL ON THE MOTOR FREELY AND THERE IS VERY MINIMAL RESISTANCE. IT ALMOST SOUNDS LIKE THE PISTON IS DRY RUBBING AGAINST THE CYLINDER WALL. THE MIXTURE SCREW WAS ABOUT 2 AND 3/4 TURNS FROM LIGHTLY SEATED. WOULDNT THAT HAVE MADE THE MIXTURE RICHER THAN LEANER? LIKE I SAID I WAS CRUISING ON THE LAKE FOR A COUPLE HOURS BEFORE THIS HAPPEND. IF IT WAS TOO LEAN WOULD IT HAVE DIED SOONER? ALSO THE MOTOR DID NOT LOCK UP. I STOPPED IT AS SOON AS IT STARTED TO SMOKE REAL BAD WHICH WASNT VERY LONG. I HOPE MY ENGINE IS NOT TOAST.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

OK I HAVE DONE A COMPRESSION TEST. I AM READING BETWEEN 28 AND 30 PSI ON BOTH CYLINDERS. I THINK I AM DOING SOMETHING WRONG THOUGH. I CANNOT CHECK IT WITH THE TROTTLE WIDE OPEN BECAUSE WHEN THE THROTTLE IS OPEN THE ENGINE WILL NOT TURN OVER. I ALSO HAVE THE BOLTS THAT HOLD THE COVER ON OFF ALONG WITH THE LOWER UNIT. IS THIS THE REASON THE READINGS ARE SO LOW. I KNOW THAT EQUAL PRESSURE ON BOTH CYLINDERS IS A GOOD SIGN. HELP ME OUT GUYS. THIS IS NEW TO ME

 

[eurolarva]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Equal numbers is a good sign if they are over 100. With mixture at the setting you described this motor did not burn up from a lean condition. Normal for that motor is about 1 1/4 turn. My guess is your impeller crapped out on you or you did not mix oil in with the gas. If you have some marine oil that you mix the gas with try squirting some of that in each cylinder and retest compression. When you have both plugs in does the flywheel still turn freely?<br /><br />By the way WOT is irrelevent on compression testing. Typically it will show no difference then at idle. Compression numbers are usually based on a warm engine however because yours does not run it would be hard to achieve that. Test it again with oil in the cylinders and make sure both plugs are out when you test each cylinder. Repost those numbers after you have tested it.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

OK I PUT A LITTLE OIL IN THE CYLINDERS AND THE NUMBERS WENT UP BY ABOUT 3 POUNDS BETWEEN 30 AND 35 POUNDS ON EACH CYLINDER. THE MOTOR DOES TURN FREELY WITH THE SPARK PLUGS IN. I TOOK A LOOK AT THE WATER PUMP IMPELLER AND IT ALMOST LOOKS TO BIG TO SPIN FREELY IN THE HOUSING. IT DOES NOT LOOK DESTROYED BUT IT IS HARD TO TURN FREELY WITH YOUR HAND WHEN IT IS INSIDE THE HOUSING.

 

[tiller7104]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Just a note I am glad to hear that everything seems to be leaning towards a viable save for your engine,"fingers crossed" The screw shows me that you are running rich, I guess with the best of both worlds rich is better. As eurolarva explained a warm engine is an ideal platform for a compression test. Just a base line my 50 runs around 140 pounds per cylinder give or take 15%. Just another thought if all things are looking good, I would consider replaceing the head gasket and really do a good test of your cooling system. I just replaced my thermostat and impeller for the heck of it and installed a tell tale. Again I wish you the best with your moter and if the Force gods are with you, a save may be in your future!

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

WHAT IS A TELL TALE AND HOW DO YOU GET ONE? I WANT TO REPLACE THE HEAD GASKET. ANOTHER THING, WHEN THE ENGINE TURNS OVER IT SOUNDS NORMAL. CAN I TELL IF THERE IS ANY DAMAGE TO THE PISTONS BY LOOKING THROUGH THE SPARK PLUG HOLES WITH A FLASHLIGHT? I ALSO BOUGHT A NEW IMPELLER FOR THE WATER PUMP PART NUMBER IS 18-3057. IT LOOKS TOO BIG. I ALSO BOUGHT A CARB REBULD KIT PART NUMBER 18-7037. ARE THESE THE RIGHT PARTS?

 

[eurolarva]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

With the compression numbers that low and you mentioned that the flywheel is easy to turn by hand with the plugs in tells me there is cylinder and probably piston damage. Two ways to test this is to remove the head gasket and take a look. Second way which is not as good is to put the lower unit in some water (garbage can) and see if it will fire up. If you can get it to run and warm up for a minute or two you can re test compression. Also post the model number of your motor and the year if you have it.

 

[tiller7104]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

I think a tell tale is the least of you problems at the moment LOL ! A tell tale is a pisser, a pee'er, stream of water shooting out of the lower caseing! Many outboards have them to see that you water pump is pumping water. I built my own with some vacume line and a 5/16 hose barb. and a piece of vacume tee. On the top of your head there is a stainless steel plug with a common screw driver head. Remove it insert the hose barb with some pipe dope or teflon tape, and route the hose thru a drilled hose in the lower housing and reduce it with a piece of vacume tee (local gas station should have an assortment of them) I bought everything that I needed at Napa. Make sure that there is adaquate distance from your hose and your head to insure you do not melt it! Just a thought! Hope this helps. As stated I would inspect your cylinder walls with the head removed, if you are going to change your head gasket anyway. Keep us informed about what you find!

 

[tiller7104]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

About you water pump impeller..I ordered one from here and for some reason they send you one for a mercury/force. I will get you the part #

 

[rodbolt]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

remove the cyl head and inspect the cyl walls for scratches, if any are present rub a penny over them, if any copper is left in the scratch its time for a set of pistons, 2 strokes wont run long with blowby gas.<br /> if the cylinders survived the overheat carefully clean and check the gasket surface on the cyl head with a striaght edge and a .003" feeler guage, if the feeler guage will slip under the straight edge at any point the head is warped and must be surfaced, then ya gotta find the cause of the meltdown, normally its a bad water pump or a bad thermostat,both are maint items, both I harp on constantly as I have found the price of the maint items never varies only the cost of the rest of the stuff if you run them until they fail.<br /> if that motor has no alarm system I would add it before going again, if it does have it test it carefully to find out why it failed to alert you.<br /> idle air fuel adjustments wont lean out the motor enough to damage it, by the time you get it that lean your fighting idle problems.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

OK. I REMOVED THE HEAD. THE CYLINDER WALLS LOOK GOOD TO ME. THERE ARE NO SCRATCHES OR GOUGES. I DID NOTICE SOME BLACK RESIDUE ON THE TOP OF THE PISTONS THAT SCRAPES OF WITH MY FINGER NAIL. THE 1ST THING I NOTICED WHEN THE HEAD CAME OFF WAS OIL ON THE WALLS OF THE CYLINDERS SO I BELIEVE I DID NOT RUN THE MOTOR LEAN. I NEED TO CLEAN THE OLD GASKET OFF THE HEAD. WHAT IS THE BEST PROCEDURE FOR DOING THIS? I PULLED THE THERMOSTAT OUT AND IT LOOKS A LITTLE ROUGH. I HAVE A FEELING THAT IS THE CAUSE OF THE OVERHEATING. HOW SHOULD A WORKING THERMOSTAT LOOK? SOUNDS LIKE A DUMB QUESTION BUT I WANT TO KNOW. SO WHAT SHOULD I DO FROM HERE WHILE THE HEAD COVER IS OFF? IS THERE ANYTHING ELSE I NEED TO LOOK AT REGARDING THE PISTONS TO TELL IF THEY NEED TO COME OUT AND HAVE NEW RINGS INSTALLED?

 

[eurolarva]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Maybe the smell was carbon burning. It has an electrical burn smell to it. I would let a force guy give you advise from here. I am the chrysler guy however when I had the exhaust gaskets off my 38 year old chrysler I was amazed at all the carbon built up. I decarb regularly however the guy before me must not have or it builds up a lot more then I expected. I soaked rags in marvel mystery oil and let it sit for the weekend then used soft wood to break off chunks of built up carbon. I bet I spent 5 straight hours working on getting the majority of it out of there. When I got it all back together again I was amazed at the sound difference and the perfomance of the motor after it was done. If it were me I would get a new head gasket and check the head as Rodbolt recommended before putting it back together again. You need to make sure if you removed the head gasket that you torque it correctly and in the correct order.

 

[roscoe]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Compression seems awfully low. <br /><br /><br />""THE 1ST THING I NOTICED WHEN THE HEAD CAME OFF WAS OIL ON THE WALLS OF THE CYLINDERS SO I BELIEVE I DID NOT RUN THE MOTOR LEAN""<br /><br />But remember, you put oil in the cylinders when you did the compression test.<br /><br />Put a water hose to the thermostat housing and then to the water tube in the midsection, Perhaps you have debris clogging the water passages.<br /><br />Look at the rings closely, no missing pieces?<br />No pieces embedded in the head?<br /><br /><br />just replace the thermostat and you will know you have a good one.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

When I said I pulled the head off I meant the cover where the spark plugs are. I have not pulled off the whole powerhead. Should I do this or go ahead and put a new gasket and cover back on along with replaceing the thermostat, impeller ,and ckecking for blockages. I also noticed that the impller viens are strait. they do not arc inside the waterpump housing. I was told by the local marina that it was more than likely the wrong impeller.

 

[eurolarva]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

If it were me I would not spend another penny on this motor till you have determined what the extent of the damage is. That means on carb kits, fuel pump kits or impellers. If the head is shot you could be looking at up to $2000 to have it fixed and It may not be worth that much to you so it would be a waste on the other stuff. Did you attempt to start the motor before you took the head gasket and cover off? Is the head gasket still in good enough condition to put back on the motor? Attached is the blow ups of a 99 force 50. You will need to post your model number because there are multiple models out there.<br />

<br /><br />Items 12 - 17 are the port side exhaust gaskets. By removing these you should be able to get a better look at the pistons to see how much damage is done. You may be able to do this without removing the power head however the bottom screws may not come out before hitting the lower cowling. <br /><br />If it is possible to reattach the head gasket, start it while it is in water then do a compression test when warm is ideal. The above posted compression numbers are not good and unless you did them wrong there is damage you can not see.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Thanks eurolarva. My model number is 507x8b. It is a 88 force 50hp outboard. I only cranked the motor to do the compression check. Is there anything I could have done wrong doing the compression check that would give me such a low reading? I had the bolts out of the cover but it was still attached with the gasket. I also had the lower unit off. The gasket is now a little deformed since i took it off.

 

[88 Bayliner Force 50]

Re: Is my motor shot? UPDATE!!!!! TEST RUN

Ok guys. I put on a new cylinder head gasket and changed the impeller and thermostat. My compression is now at 130 pounds on both cylinders. Alot more water is spitting out the back of the motor now too. I will take the boat out on the lake in a few days too see how it runs. Right now the idle is fine in neutral and does not atsll out when put into gear. I have the mixture screw about 1 and a half turns out from lightly seated. The motor is not making any noises and sounds fine. I want to put a water temp gauge in and a new warning siren. I can put the new siren in easily but how about the temp gauge? Is there anything else I need to worry about?