1988 20 HP issues

[HapaHaole]

I searched and could not find the same issue I am having with my outboard.

When I first fire it up with the choke on, the idle is low and the power is non existent. I go out on the water and get cavitation and about 7mph at WOT. While holding at WOT the engine all the sudden kicks in and out of power, takes about 7 min to kick in, then bogs and sometimes dies. Once it kicks in full power WOT it will die, then I cant gain power untill a few min later. After this, it runs at WOT with no issues.

Do you think this is a CARB issue? or electrical?

 

[Laddies]

Re: 1988 20 HP issues

Yes, clean the carb, the cavitation problem could be a bad prop hub, mark the prop and hub then test run the engine and see if the hub has moved,

 

[HapaHaole]

Re: 1988 20 HP issues

The cavitation only happens for the first 7 min of operation, after that it does not occur anymore. I will rebuild the carb to see if this helps. I also forgot to mention, the choke has to be on it all the time for it to idle correctly.

 

[Mi duckdown]

Re: 1988 20 HP issues

And the the compresion is?

 

[HapaHaole]

Re: 1988 20 HP issues

1st pull is averaging around 45 PSI, 3rd pull is 75 psi, both cylinders are the same reading.

 

[Mi duckdown]

Re: 1988 20 HP issues

Then As Laddies Posted could be spun prop .
I always like to check compression first. It just takes alot of variables out first.

 

[HapaHaole]

Re: 1988 20 HP issues

I read about the spun prop and I can tell you its not that. The motor feels like a 2 hp, then as I said after 7 min the motor goes into power. The cavitation is prob the motor after reading on the forum.

 

[HapaHaole]

Re: 1988 20 HP issues

I bought the CARB kit and rebuilt my carb. While I was doing it I noticed the Float needle was rubber and was semi sticking. The choke fuel pump diaphragm was torn among some other gaskets. I cleaned out the jets and all the ports for the carburetor, took the boat to the river and all the issues are gone. It actually idles with out the choke on. Amazing how a carburetor rebuild fixes it all. SO how often do you need to rebuild these units?

 

[Mi duckdown]

Re: 1988 20 HP issues

Nice job Hapa .Not unless you have problems . Water impellar? every couple years.

 

[HapaHaole]

Re: 1988 20 HP issues

Well that was short lived. It was great 2 times out in the water, then after letting it sit for a week I am back to square one. I found that the lower cylinder is not firing. I swapped coils, wires, and plugs and its still the same ,so I eliminated the spark. I found out the hard way the engine had no thermostat, the bolt snap off on me. I drilled it using a diamond tip burr and re-threaded the hole, then ordered the parts for it. Do you think this will fix it? by putting in a thermostat?

 

[HapaHaole]

Re: 1988 20 HP issues

OK I narrowed it down a year later.. haha

I still have no spark on cyl #2, I swapped coils and bought a new one and same thing, no fire on cyl #2. I pulled the fly wheel and checked the trigger, magnets, and the stator and they are all good.

The repair manual says to check the timing,I can't get the motor to idle at all it only runs with the choke on. Could it be the switch box?

THanks in advance