Motor will not start in the water!!!

[bcarroll]

I have a 75-79 50hp Mercury w/thunderbolt ignition. I can start it over and over on the trailer. But as soon as I pull it down into the water on the trailer it will not start. It just turns over and over. I took it off the trailer and let it float and same thing. As soon as I pull it on to trailer and back out of water...Starts....<br /><br />Please give me a clue

 

[frusterated]

Re: Motor will not start in the water!!!

This might be a long shot but have you checked compression? Maybe the load of the impeller pushing water threw the jacket is preventing the start.

 

[NathanY]

Re: Motor will not start in the water!!!

I agree with the compression, but not for the impellor, but for the back pressure that the water puts on the exhaust. Have you done any carb work on it lately? Is this a problem that has just happened?

 

[AZO]

Re: Motor will not start in the water!!!

BCarrol - check for spark when motor is in the water. If none you might have a bad ground that shows up when water enters the lower unit.

 

[papasage]

Re: Motor will not start in the water!!!

you may be idled to low did you pull up your warm up leaver .

 

[Spidybot]

Re: Motor will not start in the water!!!

Try running it in a tank when on trailer.<br />If you do not have a suitable tank, run it on muffs and hold something (hand with cloth) over the prop exhaust.<br />If you can, run it on muffs during pulling it in.<br /><br />Then you'll know if back pressure on the exhaust is the reason.