[mercury85]

I have a 85 Mercury Outboard (Model 1500). After it warms up and we are cruising at full throttle on our pontoon boat, it acts like it is bogging down and has a loss of power. I do not know much about boat motors, but it does not even seem like it is running at full power even before it warms up. Any suggestions would be appreciated. Thanks.

[Chris1956]

Is that motor an inline six? If so, it is a 1977 or earlier. There were some V6 Merc 1500s, but I did not think they made them as late as '85. OK on to your issue.

You should check the condition of the spark plugs. If they are the same and a brown ash color, they are all firing. Now check compression of all six cylinders. They should all be 100+ PSI and most importantly even.

Post back with these results, and we can determine the next step.