Johnson Motor problems

[ftgokie]

Hi everyone, I am new here....just got a boat last week from a guy that needed money. Its a 1975 Skeeter 16' boat with a 1972 Johnson 85hp outboard. He couldnt get it to run and didnt want to mess with it so he sold it to me for 100.00. I put an amplifier ( i think thats what its called) on the motor and me and my dad took it to the river to try it out. It ran great! Lots of power, motor ran smooth....everything fine.

I took the boat to the river yesterday and when I went to open it up and see how fast it would go, it would just go maybe 1/4 throttle. Nothing was different other than I filled up the plastic fuel tanks. After trying it 10 or so times, I checked the fuel bulb thinking it was a fuel problem. The fuel bulb was sucked down half way. I took it home and went and bought new hose, bulb, and connectors. The bulb is flowing the correct way, the connectors are new and now the bulb stays pressurized when running. You can put the boat in neautral, and it will rev up as high as it will go. But when you put it in gear, it starts to come up and just wont go any faster...

I suspect a fuel problem, but I dont really know anything about boat motors.

Also, where can I get parts online at a reasonable price? I need some gaskets for the little fuel block that houses the metal screen before the gas goes to the carburators. And I also need a good used prop since this one is kinda chewed up


The top pic is of the block i need gaskets for, and the bottom pic is obviously the prop I need to replace


Any help will be much appreciated.....Thanks guys

Shawn

 

[SparkieBoat]

Re: Johnson Motor problems

you can get parts on this site for your fuel pump..get the rebuild kit..it has all the gaskets..the bulb being collapsed makes me think that you did not open the vent screw on your gas tank...some old gas tanks do not have a vent..you have to loosen the cap.

good luck Sparkie

 

[crxess]

Re: Johnson Motor problems

Welcome......

You can get a replacement from Iboats or off ebay reasonable. That thingy is the Fuel pump.

The Bulb collapsing tells me the tanks vent is not working properly. Check it out or test with another tank.

 

[ftgokie]

Re: Johnson Motor problems

Thanks guys.....I ran the boat on 2 diff gas tanks, unscrewed the vent cap on both tanks and screwed them down also....same results both ways.

And the gas tanks are the ones like you buy at wal mart....plastic 6 gallon tanks

 

[Lion hunter]

Re: Johnson Motor problems

Several things you need to do.

1. Fix all leaks before proceeding. Is that wet area in the pic of the pump fuel? Alot of spark can get thrown under the hood , very dangerous.

2. Rebuild carbs. May not be the problem now but thet will need it anyway. Fresh fuel loosens alot of junk on old carbs and plugs everything up.

3. Pull pickup tubes from the tanks an see if their clogged.

4. If you still have a issue try running without the fuel cap on. Not on the water or in boat. Remove tank and place on a bench away from the motor.

Don't rev the motor above high (warm up) idle in nuetral. Their designed to have a load and will runaway reving them without. I wouldn't try to run again with that prop as well. Way out balance and can't be good for the lower unit.

 

[Rick.]

Re: Johnson Motor problems

I would check for spark also. If it lacks power it could be because it isn't getting spark to all cylinders. Best of luck. Rick.

 

[ftgokie]

Re: Johnson Motor problems

Thanks guys....I will go to Oreilly Auto tomorrow and see if they have the Sierra fuel pump kit so i can put new gaskets in the fuel pump.....and try everything on here that was suggested


I appreciate all your help guys!

Shawn

 

[ftgokie]

Re: Johnson Motor problems

I would check for spark also. If it lacks power it could be because it isn't getting spark to all cylinders. Best of luck. Rick.

Thats the first thing I checked...getting spark to all 4 cyl

 

[tashasdaddy]

Re: Johnson Motor problems

Shawn, start with the basics, before more spending more $$$.


COMPRESSION AND SPARK
i would check spark and compression first, using a $10 spark tester from auto parts store, set it as 1/2 inch gap, spark should jump that with a bright blue spark. using a screw in compression tester, you compression should be 100 psi or above, but the main thing is that the readings are with in 10 % of each other. this will tell you the health of you motor, before sinking parts into it.

it really sounds like you have enthanol poisioning. clogged carbs. read this http://forums.iboats.com/showthread.php?t=299680


fuel pump kit. http://www.iboats.com/mall/partfind...gd_poid=109272&gd_row=75&**********=983302354

fuel pump http://www.iboats.com/Sierra_18_735...z.36857--**********.983302354--view_id.174138

carb kits you will need 2 of them http://www.iboats.com/mall/partfind...gd_poid=109334&gd_row=59&**********=983302354

 

[SparkieBoat]

Re: Johnson Motor problems

my money is on the fuel pump...
Sparkie

 

[ftgokie]

Re: Johnson Motor problems

Got my fuel pump kit..was assembling it.....and the little piece in the middle that holds the metal thingy that you screw the fuel pump screen dilly whopper into broke. can you just buy the middle piece...the plastic part. Or do I have to buy the whole fuel pump?

I am seriously thinking of jb welding the broken piece back on, just to see if it works

Here is a pic of the part that broke

 

[SparkieBoat]

Re: Johnson Motor problems

I would probably replace the part...no need to get stranded because of it.
be Careful with plastic parts...lol Now I tell you huh.
Sparkie

 

[a70eliminator]

Re: Johnson Motor problems

Sounds like you eat your pride and get your Dad over there, no just kidding your on the right track.