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View Full Version : 1989 Force 50 hp no power



chris_beougher
04-28-2009, 04:27 AM
I have a 1989 Force 50 hp outboard. The motor starts and runs fine but will not run over 5 maybe 10 mph i have no tach but its running steady. The motor had this problem when I bought the boat so dont know if the rpms are where they are supposed to be. Is is possible that I am running off of one cylinder. The top spark plug has oil and grease on it when removed and the bottom appears to have just came out of the box and are both a little over a year old. Any ideas?

gonzo25
04-28-2009, 12:17 PM
"A COUPLE OF QUESTIONS. This motor had this problem when you bought it, meaning that it had never been fixed but is as it was when you bought it, right? was this boat stored for a while and hadn't been used, or had it been used on a regular basis, or do you know?
the top plug looks like it has oil and grease on it, is that what it is, or is it gas? remember there is oil in the gas too. when you say the bottom one looks like it just came out of the box, does that mean it looks new like it has never been fired or does it look like it has been used but is spotless clean with no black or build up at the electrode? next is the rpm... the rpm does go up you just don't know how high or how high it should be right? when you are trying to go and give it full throtle does it just feel like no power or does it feel like a car that the clutch is slipping on? this motor will run and sound fine on one cylinder, but the rpm response will be slow.
This is what i would do, since you don't really know this motor. start with a compression test, but most importand do a leak down test, that will tell you if you are losing compresson at rings and most important seals. you can get a leak down tester at harbor freight for under $30, while your there get a spark tester because that is what you need to do next. they are under $10. goes on spark plug with a lead to the plug wire and will show spark. check for spark, what does the spark look like at the plug, does it look weak or is it crisp and blue. just because plugs are new doen't mean that they aren't questionable, along with what is making them work.
An important question is, was this boat stored for a while before you bought it, or was is used on a regular basis? if it was stored for a while, my guess would be the fuel pump. also, if it had been stored for a while, change the impeller in the water pump, BEFORE you go out and start using it. a cheap and easy job that will protect your investment more than anything else you can do, other than keeping the 2 stroke oil in it.
after the motor has run, do both plugs feel hot? if you put your hand on the top and bottom cylinder, do they both feel hot or is one cooler?
if the top clylinder has spark but doesn't feel hot after the motor has run for a few min. along with it being wet... check the fuel pump. it works off of the top cylinder and if there is a hole in the diaphram it will put gas into that cylinder, to much gas and it won't fire.
if both cylinders have spark and are hot, and one has a clean, clean looking plug... it indicates warer in the cylinder. water turns to steam and that is why plug is clean.
if the motor is running good and it feels like the clutch in a car is slipping... lots of rpm but no mph.... check the prop. the prop has a rubber core and sometimes they separate and the prop will not spin like it should.
REMEMBER. spark, fuel, compression. those are the three things that make a motor work, check them in that order.
DO YOU HAVE A MANUAL? If you don't have a manual, then don't work on your motor! I was talking to him the other day and God told me that he uses two manuals when he works on his Harley.
would you want someone to operate on you that had never read a medical book?"

chris_beougher
04-29-2009, 12:21 AM
"Yes, I bought this boat last summer and the guys i bought it from said it had been sitting for about three years since the last time it was used. When i purchased it I did change the impeller, drained all of the gas in the tank along with changing the fuel lines and put a couple inline fuel filters in to make sure I did not have any of that old crusty gas getting through. The bottom spark plug does appear to be used but no build up. I do no have a tank to run it in and see if the plugs and cylinders are getting hot so I will be sure and post as soon as I get a chance to get down to the lake. I appreciate all of the advice I will be running these tests and let you know what I find out."

mn_jack76
06-01-2009, 11:14 PM
"<font color=""0000ff"">I have the same issue with low power and one plug clean and the other dirty &#40;force 50&#41;. I doubt it&#39;s a case of a fuel pump failure or a head gasket, as my head gasket failed last year and it wouldn&#39;t start at all until I fixed it. I haven&#39;t looked at my motor yet beyond pulling the plugs, but it sure looks like a non-firing cylinder due to a bad connection, a bad coil, a short in the high tension lead or... I&#39;ll let you know.</font>"

gonzo25
06-02-2009, 02:17 AM
"okay Jack, I don&#39;t understand your post. are you just making a statement or are you asking how to check the things you thought were in question? like i said in my first post, it takes three things to make a motor work, spark, fuek, and compression...check them in that order. since you didn&#39;t say your boat had been stored for three years before you bought it and it had the problem then, i would assume that you have been using it up to the point that you have this problem. you can tell if a cylinder isn&#39;t firing at all because it will not get hot to the touch after it has run for a few minutes, pull the plug. it should be wet with gas... no spark or bad fuel pump will both leave it wet, but start with spark first. do you have a spark tester, or a timing light? if not the plug wite from the other cylinder and ground it, then hook up the plug from the questionable cyl. and ground the plug. move it away from the plugs hole so if it does have spark you won&#39;t end up with a ball of flam from the gas coming out of the spark plug hole. turn the motor over and see if there is spark at the plug, and if there is, is it weak or crisp and blue. if it is crisp and blue it will probably be the fuel pump. if you have a timing light just hook it up and start the motor, if you aren&#39;t getting anything to the plug the timing light isn&#39;t going to flash. If you have water in the cylinder it turns to steam and the plug will look very clean, but it won&#39;t be wet with gas. these motors will run on one cylinder and they will run with a blown head gasket. a blown head gasket can have different causes for it blowing and different symptoms and different sevarities. electrical problems are easy to figure out when it just doesn&#39;t work, but they are usually intermitant because when coils or condenser or points get hot they will stop working, and then when they cool down they start working again and it make it harder to figure out what the problem is... if it doesn&#39;t work at all it is just a matter of illimination. since you didn&#39;t give the year of the motor i have no clue what kind of ing. system it has, but the principle is the same on all of them. good luck"