Johnson 70hp won't start
 

I have a 70HP Johnson apprx 1994 model with oil injection. Problem is
when cold engine fires no problem and runs great, it's top end is fine
and idles great. No problem yet, go fishing for a half hour or so and
she will not start again. If I give it a squirt of starting
fluid(ouch) kicks over and runs fine. When it will not start the plugs
are relatively dry, if I wait for about an hour it will stat again,
maybe! When cold starts fine when warm, iffy at best. Any help would
be greatly appreciated,
Thanks