mercury 150 xr2 blackmax (1985) sn A157375

[uboat39]

Boat runs good cold for about 400ft then it falls on its face. Idles good all the time. Idles but will not come up out of water. If you rise th motor up and down it will sometimes take off like it should, but other times it will not. What do I do?<br />Comp. test on above. # 1. 105 #2 105 #3 108 <br /> # 4. 110 #5 105 #6 110<br />Spark OK

 

[rodbolt]

Re: mercury 150 xr2 blackmax (1985) sn A157375

sounds like the cylinders are running out of fuel. but first test the spark and compression. post back the numbers and we can help. under a post for badbass I gave him directions to make a quik spark tester in the yamaha forums, try it only make yours a 7/16ths gap.