1964 65 h.p. merc wont go in water?

[mmreagan200]

this motor run at idle well but in water it wont<br />get no rpms in water but will rev fine out of water? carbs were badly clogged so i rebuilt them and put in new fuel pumps.<br />my compression is 130-135 in all 4 cylinders can any one help?

 

[mellowyellow]

Re: 1964 65 h.p. merc wont go in water?

welcome aboard,<br />sounds like your dropping cylinders. pull plug wires one at a time, if no change in performance when a wire is pulled, that is dead cylinder.<br />good luck,<br />M.Y.

 

[mmreagan200]

Re: 1964 65 h.p. merc wont go in water?

i dont mean to sound silly but what do you mean when you say dropping cylinders? is that an electical problem or is it in th cylinders?

 

[mellowyellow]

Re: 1964 65 h.p. merc wont go in water?

sorry, means spark... that cyl. is not firin.<br />good luck,<br />M.Y.

 

[mmreagan200]

Re: 1964 65 h.p. merc wont go in water?

thankyou ill try that today

 

[mellowyellow]

Re: 1964 65 h.p. merc wont go in water?

also make sure your prop hub isn't spun.

 

[Chinewalker]

Re: 1964 65 h.p. merc wont go in water?

If it's a group of two cylinders (two top or two bottom) that aren't firing, it might be that associated carburetor not feeding fuel. Any outboard will SOUND fine on the hose when it's not running on all cylinders. It'll rev up nicely giving the illusion that it's making full power, when in fact it's just taking advantage of no load and minimal exhaust back pressure to make it sound like that. In the water, under load it's much easier to pick out the fact that it may not be running on all cylinders...<br />- Scott

 

[mmreagan200]

Re: 1964 65 h.p. merc wont go in water?

well, ive tested for spark and i am getting fire in all 4 cylinders,and the carbs are rebuilt so i am sure im getting fuel? is it possible a bad reed valve could cause the problem under load?

 

[mellowyellow]

Re: 1964 65 h.p. merc wont go in water?

ok, start with cheapest fix first.<br />go back over fuel system and check for air leaks<br />or flow problems. does primer bulb get/stay hard?<br />when you squeeze bulb, do you see gas spilling<br />out of front of carbs? did you install new pump<br />kits? is tank vented? clean fuel 50/1 mix?<br />once these things are eliminated, time to look<br />at electrical. bad switchbox etc.<br />do you have a tach?<br />good luck,<br />M.Y.