Is my 86 Johnson 4hp pumping water?

[cajun66]

How do I know if the impeller is doing it's thing? I ran the motor for the first time in several years and noticed that the head got real warm. Motor calls for 100:1 fuelil and I was running 50:1 so I know it wasn't lean.

 

[lexkyboater]

Re: Is my 86 Johnson 4hp pumping water?

If you haven't seen this yet - http://forums.iboats.com/showthread.php?t=158076 - this is to decarb your cylinders and get your rings to unstick, which is likely if it's been sitting for a while. Also, if it's been sitting the guys here recommend replacing at least the water pump impeller as the rubber in the impeller tends to dry rot easily. That will probably run less than $20 and it's not hard to change, but everyone recommends a manual. They also recommend 50:1 for those engines that called for 100:1 from what I've read. On that motor, if it has a small orifice that pees water, it should be a steady stream, or if it's a larger port with exhaust, it mists and increases water output as you move forward with it in gear. As far as the temperature, you can get temperature sticks - crayons - that melt at certain temperatures in 5 or 10 degree increments. It should run from 140 - 145 degrees from what I've read, or at a temp that lets you hold your fingertips to the cylinders for no more than 3 seconds without burning them. --Steve

 

[samo_ott]

Re: Is my 86 Johnson 4hp pumping water?

I tried to get those temp sticks at my local OMC dealer and they laughed and said they never use em. What works well is the new fangled infrared thermometers... You just point it at the head and click and presto, you get the temp instantly. They cost a tad though, ~$50 or so, but work well.

 

[cajun66]

Re: Is my 86 Johnson 4hp pumping water?

It should run from 140 - 145 degrees from what I've read, or at a temp that lets you hold your fingertips to the cylinders for no more than 3 seconds without burning them. --Steve

Great. It didn't get THAT hot after running a few minutes. I priced the inpeller at NAPA at 17 bucks which I'll get tomorrow.

Thanks a lot.

P.S. I have a infrared thermometer at work (diesel mech)

 

[lark2004]

Re: Is my 86 Johnson 4hp pumping water?

These motors do not have a pee hole, they dump the water into the exhaust housing.

The head will get pretty hot as well, due to the only cooling for the head being a small chanel that runs around the edge. The best place to feel the engine is on the side that has the freeze plug, the other side has the exhaust cover which also runs pretty hot.

 

[cajun66]

Re: Is my 86 Johnson 4hp pumping water?

Thanks.