4 HP Seahorse Dry Plugs

[Stonets]

I'm working on a 1970 Johnson Seahorse 4 HP. Compression test are 93 top and 95 down. It won't start at all. Took the plugs out and they are both totally dry no sign of fuel. So I cleaned the carb inside and out with a kit still no go. I went further and replaced reeds. Still no go and both plugs are still dry...I am at the point don't know what else to do . Any help would be appreciated!!

 

[racerone]

Time to test spark.----Do this testing,---Will spark jump a gap of 1/4" or more, yes or no ??--Please note that the sparkplugs are not used during this test.

 

[Stonets]

thanks! I don't have a tester at the moment but I did test with a plug grounded on cowling and was able to see strong blueish sparks, does it jump 1/4 or more I don't really know. I will get a tester to test it. However, my question is though...I put two brand new plugs in it then keep pulling then took the plugs out and they still bone dry with not even a smell of fuel. So that's why I suspect something in the fuel side...

 

[F_R]

OK, since you are so convinced it isn't getting fuel have you tried squirting a bit of fuel in through the carburetor to see if it will fire? I don't know if you have a fuel problem or not, and neither do you. But the spark test is a question that must be dealt with as a first diagnostic step. Don't get hung up on the dry plugs thing. They aren't supposed to be real wet. If they were wet, it may indicate a flooded condition.

However, if you have good spark and you know the carburetor is clean and adjusted somewhere near correctly, you MAY have a crankcase compression problem. You say it isn't the reeds, so we are on a witch hunt. But before we go that far, check that spark. (And make sure the plug wires are on the right plugs).

 

[Crosbyman]

to what extent was the carb cleaned.....did you soak the body in cleaner and blow out all the carb channels with a strong air supply.

is fuel entering the float chamber did you do blow test on the carb

 

[Stonets]

I will definitely get a spark tester and see what I will get...it is kind of hard to spay the fuel to the carb as really no much space there. Can I spray fuel directly into the spark plug hole instead?? another question...how much suction should I expect from the intake manifold (the hole connects to the carb)? I put a tissue in front of the hole and pull I do see some suction but really not that much but again...I don't know what I should expect...

 

[Vic.S]

I will definitely get a spark tester and see what I will get...it is kind of hard to spay the fuel to the carb as really no much space there. Can I spray fuel directly into the spark plug hole instead?? another question...how much suction should I expect from the intake manifold (the hole connects to the carb)? I put a tissue in front of the hole and pull I do see some suction but really not that much but again...I don't know what I should expect...

You can improvise some means of testing for a good spark without buying a tester.
Plug leads on the correct plugs? Not swapped over ?

But in view of the apparent lack of fuel getting into the engine:

Are you sure the carb is filling with fuel correctly when you prime it with the bulb?
Float installed correctly and set to give the correct fuel level?

Are the mixture adjustment needles correctly set?
Not done something stupid like seating them too firmly and breaking the tips off in the orifices ?

Choke flap closing correctly?

Carb throttle plate opening correctly ?

 

[Stonets]

yes Crosbyman, the carb is sparkling clean, yes soaked and blew with compressed air.

Vic, that's exactly my my headache, the spark tester I can get is really crabby and the good ones I have to order online...just thinking if I can DIY one. I did check the items that you mentioned and did swapped the plug cable and no difference.

So really, can I spary mixed fuel in the plug hole directly? and what kind of the suction should I expect from the intake manifold hole? Before I can get the spark tester, anything I can check for the crankseal? Crankseal is the area I haven't visited before and don't really know how and where??

 

[F_R]

Of course you can spray fuel in the plug hole. But don't over do it. Too much fuel won't run either. Why don't you keep it simple on the spark test? You don't need to buy a tester. Stick a #2 phillips screwdriver into the plug boot and hold the shank about 1/4" away from the corner of a head bolt. It should jump the gap. I know you aren't going to get it exactly 1/4" but try it a few pulls and see what happens.

There is only one actual crankcase seal on that motor, on the upper end of the crankshaft. Everything else relies on bearing fit. Unless the motor is worn out, the bearing fit should be ok. The gasket between the reed plate and crankcase could be blown between the upper and lower chambers, but unlikely.

 

[Canoe2]

I had a similar problem with a 72 4 hp, tried all the suggestions listed above - worked when i sprayed fuel into the cylinder, then through the throat of the carb, but never when set up normally. Was about to give up on it when i tried a new fuel pump. Worked great and the thing ran like a top after. Think i had some blockage that was preventing the carb from suctioning. Might be worth a try.

 

[Crosbyman]

back to basics........is fuel reaching the carb or not ????????! and that carb is not hard to blow fuel into it !!!

air fuel fire you have 2 so get some fuel in the carb !!!

 

[Stonets]

F_R thanks for the great tip!
Canoe2, I do have a spare fuel pump will give a try. But just what confused me is that if I already got fuel in the carb it should just start and run till it runs out of fuel...or the fuel pump will affect suction in anyway??
Crosbyman, yes I'm sure fuel reached the carb and if I keep pulling with the hose on it will actually flood the carb...
I will try a few things and circle back with result.

thanks for all the help folks!

 

[tomhath]

Is the choke closing? Is the throttle opening?

 

[F_R]

Fuel pump has absolutely nothing to do with starting the motor. It's only purpose in life is to pump gas from the tank to the carburetor to keep it running after it is started. I say that with one - actually two- "buts" though. If for some reason, gas can't flow through the pump, you can't fill the carburetor or start the motor. Finally, if the pump diaphragm is ruptured, it will pour great amounts of gas into one cylinder, flooding it.

 

[Stonets]

Tomhath, yes choke and throttle both functions no problem.

F_R, I just tested the fuel pump, gas getting through no problem, squeeze the prime bulb about twice till it become firm and stop. unplug the hose connects the carb, it spills instantly after I unplug the hose, then I tried to pull and could see it spit fuel drops.

Spark test good. both jump to around 5~6 mm and bluish.

the plugs are just totally dry...barely smell of fuel.

So at this point, does it point to the crankseal? is there a way to test it or should I go straight to take it apart?? or anything else should I try?

 

[Crosbyman]

stonets.... can u feel suction if you put your hand in front of the carb face when you pull the starter rope ???

 

[F_R]

Tomhath, yes choke and throttle both functions no problem.

F_R, I just tested the fuel pump, gas getting through no problem, squeeze the prime bulb about twice till it become firm and stop. unplug the hose connects the carb, it spills instantly after I unplug the hose, then I tried to pull and could see it spit fuel drops.

Spark test good. both jump to around 5~6 mm and bluish.

the plugs are just totally dry...barely smell of fuel.

So at this point, does it point to the crankseal? is there a way to test it or should I go straight to take it apart?? or anything else should I try?

Well, since I don't know what the problem is that is a hard question to answer. Everything you tell us seems to indicate it should run. Personally, I doubt a teardown is necessary. But as I said, I don't know what is necessary. I guess what I'm saying is I wouldn't tear it down for an exploratory without a diagnosis. Are there any signs of previous severe overheating? Is there any loosness to the main bearings? When you spin it with the plugs out, can you detect any "plop plop" sound of crankcase compression? Did you try injecting some fuel yet?

 

[Stonets]

Crosbyman, just went to do it. I can't say I felt much if I put my hand there. then I put a piece of tissue and tape it around the carb face then pull it I could see some suction movement...not a lot but the tissue was moving. I did similiar test before when I had carb removed, tissue in front of the intake manifold hold, got similiar movement. And more to it...when I tried to replace the reeds, again put a tissue in front of the reeds, I could see the shapes of the four reeds taking turns showed on the tissue...

 

[Stonets]

F_R, I haven't tried injecting fuel yet...will do that in the next couple days.
I just went to spin it and no much that I could hear. I know what you are referring to though, I heard that when I spin my 15 hp evinrude.
Time to tell the "history" of this motor - in fact I don't know the history This is the very first motor that I bought from kijiji 3 years ago. The guy claimed it works and obviously it did not and of cause the guy dissapear when I asked further questions, what can you expect from a kijiji transcation...Back then I was so naive and did not even ask for a tank test and quite honestly I had very limited knowledge at the time. Then in the past couple years I had gained some experience with a few other motors and boats etc...this motor showed up when I cleaned my garage last week. It really look very clean and have nice cylinder compressions. So it got me itch again and it bothers me if I can't fix it ...

 

[steelespike]

If the crank seal was bad it would seem that it would be oily under the flywheel.
With the plugs out You should here the puck-puck crankcase compression sound.
Do the fuel in the plug hole.