could this be carburetor trouble

[RTripp]

just bought 1980 15 hp johnson. Man pulled it out of the back of his truck placed it on a stand, hooked up ear muffs, pulled cord once, no start, pulled joke, it almost started, put choke back in and pulled and it started and ran great. Went through all the check points. Good compression, good spark and it idled pretty good. Would have to turn throttle every now and then to keep it idling.

I bought it.....took it out and it ran good for about a half hour. Pushed my old sears 11.5 foot boat 22 mph. Then....it started coughing and sputtering. Sputtered back to the launch and took it back to the guy. He is a mechanic. Left it with him and nest day he cleaned the carb. And it ran good again.

Took a fifteen mile ride and it only coughed once for a few seconds and then ran really well for the rest of the way back to the launch. The no wake zone is about a half mile long.

Trailered it home and put it in garbage can full of water to flush it out and it would not crank.

Took it back to mechanic and he tried to pull start it. Wouldn't crank. New plugs. So....he put the drill on the fly wheel and it took awhile but it cranked and seemed to run well.

Next time out. I went through the 1/2 mile of no wake zone and then began to crank the throttle. I then said "OK lets go!"
However; the throttle was already wide open and I was going 3 mph. I kept going another 1/2 mile but it never got better.

I had my trusty 4 hp evinrude with me and I swapped out motors to still have a day of fishing.

Got home and put it in the garbage can and it cranked up but when I went to advance the throttle the rpm's advanced, unlike on the water pushing the boat, I took it to almost full rpm but it began to smoke like crazy.

It was like a the old mosquito fogger.

Could this be carburetor trouble?

 

[racerone]

Could be.----But check the fuel pump diaphragm.----And was a new water pump impeller installed , yes or no ?

 

[boobie]

What's the compression on it ??

 

[RTripp]

water impeller works great if the flow coming out of the pee hole is any indication

I actually just took mechanics word on compression. The mechanic is a nephew of a good friend who is also an auto mechanic and he was there at the time and assisted with the cleaning of the carb. I'll go to Reilly's Auto today and borrow their compression tester

 

[RTripp]

I'm not a mechanic. But, I do try to fix things myself. However; I tried to make the starter coil work better and I totally screwed that up. Now I am starting the motor with a drill.

I'm a little scared about taking the fuel pump apart as I could screw that up, too. If I get a few more opinions on this problem being caused by fuel pump I will buy one as I see they are around $50

 

[racerone]

?---Why not operate the manual pump as a test ?----Those pumps are easy to repair / inspect.---But that is my opinion and some will argue that.------If you can solve it with money you do not have any problems.

 

[RTripp]

is there a video on how to operate the manual pump test.

I'm not a mechanic but I have fixed a lot of things from watching youtube videos....tv's, washers, dryers, ovens, air-conditioners, etc.
I thought I was fixing the starter coil, but I haven't been successful with that one.

Thank you for all responses

 

[racerone]

?---The primer bulb on the hose is a manual fuel pump.---Does the motor run properly when you operate it ???

 

[RTripp]

got compression tester from Orielly's. Started engine and it runs pretty good. Never used a compression tester before but I did read and followed the instructions. just tried compression check and i get 0 in both cylinders maybe tester is any good.

I cranked motor with ear muffs on. I did not want to rev the rpms too high but I took it up to about 3/4's. Turned it off, took out spark plug, opened throttle and pulled choke. Spun flywheel for a few seconds with drill, repeated four times and I get 0 reading.

When the motor was running I pumped the bulb which had no effect.

Motor seems to run pretty good. It just wouldn't push boat beyond 3-4 mph at full throttle. When it's here on the muffs or garbage can it seems to be very powerful.

 

[Fed]

Cranking isn't running.
If it's running along but won't speed up as the rpm goes up you may have spun a prop bush.

 

[tomhath]

It sounds like it doesn't run well after it's warmed up a bit. I'd replace the head gasket; they don't cost much and it's easy to do. You can clean the water passages while you have the head off.

 

[boobie]

Before you do anything else get a decent compression gauge and reading.

 

[RTripp]

compression tester from O'Reillys didn't work - returned it and got one that does work

85 in the top and 95 in the bottom. Top has a little oil in the spark plug hole and the bottom does not.

 

[racerone]

Does spark jump an actual gap of 3/8" or more on both leads , yes or no

 

[RTripp]

Quote from Fed-------If it's running along but won't speed up as the rpm goes up you may have spun a prop bush.

Well....if it is the prop bush would that make the motor sound terrible.

the rpms rev perfectly with muffs or in garbage can. But the motor when pushing the boat sounded like MAYBE it was running on one cylinder. However; I don't really know what one cylinder sounds like. It was just running rough and wouldn't go faster than 3 mph. It sounded sick. I was hoping it would clear something out of somewhere and begin to run properly. But, after 1/2 mile and no improvement I took it off and put my 4 hp evinrude on.

 

[RTripp]

Quote from racerone -- Does spark jump an actual gap of 3/8" or more on both leads , yes or no

I'm going out to see right now

 

[RTripp]

Both spark plugs shot out spark at least 3/8" and more

 

[Fed]

Sorry tripp I took you at your word.

Motor seems to run pretty good. It just wouldn't push boat beyond 3-4 mph at full throttle.

 

[racerone]

Start the motor and at idle pull one plug wire off at a time and report what happens.----Perhaps check reed valves too.----

 

[RTripp]

Fed says--------------Sorry tripp I took you at your word.
Because I said------Motor seems to run pretty good. It just wouldn't push boat beyond 3-4 mph at full throttle.

I meant to say-It seems to run good on ear muffs and in garbage can But not when it was trying to push boat

Leaving the launch that day I had to go through a 1/4 mile of no wake zone. It was low tide and I was kicking up lots of mud. Maybe it does have something to do with a spun prop. But that doesn't seem to be the issue due to the fact that the motor was sounding like it was having trouble

Its only 7:30 am here so I will wait til 8:30 to crank the motor and pull spark plug wires.

I don't know what reed valves are. But, I will google/youtube it now.