1988 50hp Problems....

[spectrum14]

Hi, I have a 1988 50hp johnson. I think i probably have more than on problem, but i don't really have any idea how outboard work. I guess ill just give a run down of what i have to do to get the motor running and going. To get it to start are after couple of days you have to pull the cold start lever all the way up and choke the hell out of it, and once it starts you have to keep pushing the choke or it will die. The cold start lever is up the whole time. After a while of this it gets warmed and and i push down the cold start lever and go, but i can't let it idle. I have to take right off. Once i start moving it seems to run good and i run it to the other side of a small lake. It seems to have a lot of power. When i come to a stop it will idle really high for a while and then sputter and shake then die. To get is started again i have to pull the cold start lever and choke the hell out of it again. I think all of the basic stuff is ok, but i am not totally sure. I just checked the compression and it was 110 top 130 bottom. I thought that was kind of a big difference, but im thinking that isn't my only problem. Help

Thank You

 

[psteurer]

Re: 1988 50hp Problems....

Your compression numbers are not too good although not terrible. The two cylinders should be within 10% or each other. Recommend a decarb and retest. You can find the procedure here: http://forums.iboats.com/showthread.php?t=299680

As you suspect, there also could be a problem in the carburetors and probably in the idle circuit. You can do a rebuild of the carburetors also described in the link above. Hopefully your compression numbers will improve to get closer to the 10% tolerance.

 

[spectrum14]

Re: 1988 50hp Problems....

Thank you, i will try that. Is the idle circuit in the carb. I took the boat to a mechanic, and i said the problem was in the carbs. He rebuilt them, but it didn't run any better after that. I am just very frustrated with this, it seems that every couple times i take it out it does something different. A couple months ago it would run great until it got warmed up and then it would not idle or run at low throttle.

 

[tashasdaddy]

Re: 1988 50hp Problems....

i have had several of those motors. it sounds like the mech did not get the carbs completely clean. do you pump up the fuel line before you try to start?

see the top secret file, carb cleaning. have you check spark?

 

[spectrum14]

Re: 1988 50hp Problems....

yeah i think that the spark is good, but i just checked it by looking at it. I don't know if that is the right way. If i bought a rebuild kit would that clean up the carbs. The mechanic said that he adjusted the floats and put two new gaskets on the bottom of each carb where i think the floats are.

 

[psteurer]

Re: 1988 50hp Problems....

Rebuilding the carbs means thoroughly cleaning all the internal passage ways and then using a rebuild kit to to replace parts. This includes removing the high and intermediate speed jets. There are some tricks to it but it is not difficult. Your carburetor has 3 circuits: idle, intermediate and high speed circuits. Sounds like you have a problem in the idle circuit right now. When you remove the carbs, look down the barrel from the end it is attached to the motor. You will barely see 2-3 small holes that touch the throttle plate. Make sure these don't have crude in them. Use a copper or brass wire to clean them out. Check out the top secret file: http://forums.iboats.com/showthread.php?t=244013

Your carburetor may have all kinds of black crude in it when you disassemble. If you do, then your fuel lines are deteriorating due to the ethanol in the gas. You should replace them all if that is the case or do it for prevention. Also, for the future run some type of fuel stabilizer like Stabil or Sea Foam in your gase. THis is especially important if your motor sits for 2-3 week or more at a time.

You might want to check the spark. Get a spark tester and see that the spark jumps 1/2 inch. Good to buy a manual if you plan on doing the work yourself.