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help . . . boat only starts on driveway

J

Jackson Hokanson

New member
1990 40 HP Johnson outboard with oil injection

I'll post a video. I had not taken the boat out in a year and a half and decided I would put some plugs, change the oil out from the stuff the boat had in the reservoir when I bought it to the synthetic XD50 (it was blue verse the red stuff I had in it) recommended by a boat mechanic. I also changed the gear-case oil in the lower end.

I was out a week ago when the warning horn went off in the dash intermittently. I was told it was probably an air bubble that caused a low oil event, but I should probably change the impeller with a water pump kit. I got a water pump rebuild kit off Iboat and it started right up in my drive way and idled and ran for 30-40 minutes (I did end up with an extra bolt). I tried to take the boat to the lake today and I could not get the engine started with the boat in the water. As soon as I got home it started right up in my driveway again, but it started overheating (the solid warning horn came on)

I was thinking I should drop the boot and see it my water pump is holding up, but I am not an experienced outboard mechanic. I can work on cars okay with the help of youtube, but I wanted to see if anyone had any thoughts or suggestions to why a boat would run at home with a hose but not start when submerged???

any thoughts or suggestions?
 
A compression test should be #1 test to see if the overheating damaged the pistons or head gasket. I have to assume you know how to start it. (Don't be offended, you would be surprised at how many people don't know you have to give it some throttle).
 
fdrgator said:
A compression test should be #1 test to see if the overheating damaged the pistons or head gasket. I have to assume you know how to start it. (Don't be offended, you would be surprised at how many people don't know you have to give it some throttle).
Click to expand...

compression.jpg
This is what I got for compression test (you can click the image to make it bigger). Should I run the engine until the alarm goes on and then check compression? Or should I skip that part to prevent any further damage to the engine?
 
Help, my johnson 50hp will start everytime in the driveway, but never starts in the water.
I just ran the boat in the driveway, and ran a wire from hull to outside of outboard and it shorts out the motor.
How can I fix this please
 
You have a bolt left over!? Find out where it's supposed to be and install it.... under the trim tab?

********************
(Engine Won't Start or Hard Starting In Water)
(Joe Reeves)

The Evinrude and Johnson engines, starting in 1973, have what is called Magneto Capacitance Discharge ignition, self contained, not dependent on battery voltage. The engine must turn over at least 300 rpms in order for the flywheel magnets rotating past the stator ignition generating coils to supply approximately 300v AC to the powerpack(s), which in turn is needed to supply power to the coils etc etc (spark).


In the water, exhaust back pressure is encountered due to the fact that the exhaust housing (housing between the powerhead and the lower unit) is filled with water. This would drag down the needed rpms, affecting ignition.

Normally the clue to this type problem is that the engine starts fine on a flushette (hose), but is very difficult to start when in the water.


Should this be the case, check the battery, clean and tighten all conections (use a wrench or pliers, not your fingers). Any cable that gets overly warm or hot indicates either a loose, or tight but dirty, or internally corroded cable. And of course check the starter itself.
 
PaulOlsen said:
Help, my johnson 50hp will start everytime in the driveway, but never starts in the water.
I just ran the boat in the driveway, and ran a wire from hull to outside of outboard and it shorts out the motor.
How can I fix this please
Click to expand...
Start your own thread don't hi-jack 2 year old ones. What is the model # of the motor? Have you done a spark and compression test?
 
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