1976 merc 1150 bogs at high speed....sometimes

[phatmanmike]

hey guys, dudes, mates, blokes, and where ever else you may be....<br /><br />i cruise at about 4200 rpm. sometimes( not always) the motor will bog and slow down all the way to idle and then die. alsmost as if it ran out of gas. but i have a firm bulb and a clear filter so i can see the fuel flowing, the filter stays full.<br /><br />after it dies, i can restart it and all will be fine. its not a constant thing, but it happens at least once every outing, sometimes more.<br /><br />heres what i have done since aquiring motor:<br />rebuilt/cleaned carbs( although still has origonal floats)<br />rebuilt fuel pump.<br />all new fuel lines.<br />new plugs.<br />timing is ok as per speck.<br />new wire harnes.<br />new controls & cables.<br />new rectifier, twice(since may)<br />new coil.<br />compression 155lbs - 160 lbs in all 6cyl<br />decarbed.<br /><br />i know it sounds fuel related. i use the red 6 gallon plastic tanks. if i take the fuel line off and just stick it in the large opening used foe filling the tank, it seems to not do it anymore.?!? as i said, its not a constant, its very random.<br /><br />motor sat inside a garage for 20 years when i aquired it. everything is all origonal. all electronics.<br /><br />im usually the one answering the questions, but now i need to be on the other side of the coin.<br /><br />any ideas?<br /><br />m ikey

 

[yclip]

Re: 1976 merc 1150 bogs at high speed....sometimes

fuel pump diaphram

 

[jheron]

Re: 1976 merc 1150 bogs at high speed....sometimes

Check your fuel tank vent. Try just leaving the fuel cap open for a day and see if that makes a differance <br />Regards Jon

 

[Chris1956]

Re: 1976 merc 1150 bogs at high speed....sometimes

Mike, I do not know it this applies to your motor, but the back-drag carbs have a fuel screen in the top of each carb, under the brass elbow or tee. I do not think this is your issue, but some years ago, mine clogged up, and I did not even know they existed (not in manual or parts list). It was a B*&^% to find!