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Motor won't start when submerged
I have a 1976 70HP motor. I just re built the water pump and added new gear oil to the lower unit and bolted it back on. It starts up fine when it has ear muffs on it but once I trailer it down to the pond or submerge it in a barrel of water. The motor won't start up and run. If I put the ear muffs back on it fires up but not when water covers the prop completely. What could possibly be wrong with it? :confused my local mechanic and I are completely confused on this issue. It does also run with ear muffs on if the cover is on our off.
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I a$$ume you mean that the engine won't start when the rig is launched or sat in a test tank of some king (submerged = underwater!)... however, it's obvious what you're saying.
Sounds like the engine is cranking over too slowly... OR... perhaps the stator is encountering a meltdown. The engine must crank over at least 300 rpm for the stator to generate the proper AC voltage to the powerpack's capacitor, needed to energize the powerpack.
The stator under the flywheel can be checked visually for a meltdown. Look closely at it. If there is any cracks and/or a sticky substance dripping down on the timer base and powerhead area, that would result in a AC voltage drop to the powerpack. Should this condition exist, replace the stator. This condition, when it begins, may result in perfect spark when the engine is cold...BUT... after it warms up, then shut down to fish a bit or whatever and all that engine heat rises to the flywheel and stator area, that stator fails, resulting in weak, erratic, and eventually no spark! A stator in this meltdown condition requires replacing regardless of whatever reading one may get out of it.
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(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.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:
joe_omc32 | eBay
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Bad Stater?
I can get the motor to crank over with ear muffs and run perfect with them. I'm also able to engage both forward and reverse at full speeds for long periods of time. But like I said once water cover the prop and exhaust vents that does not work. Is this still an indication of a bad stater? The starter will still spin the fly wheel though while its submerged and no smoking of wires since all connections to battery are tight. Thanks for your help.Comment
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Đất Mặt tiền HTP nh* bè 5*40 thổ cư 154m2 giá 3,9 tỉ tluong chút tiếp khách thiện ch* MTG -QC, Lhe Mr Tâm 0936386879Comment
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Đất Mặt tiền HTP nh* bè 5*40 thổ cư 154m2 giá 3,9 tỉ tluong chút tiếp khách thiện ch* MTG -QC, Lhe Mr Tâm 0936386879Comment
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