1990 70 HP Evinrude Need Help No power

Bought this on a whaler over the summer - it had sat for 10 years - took it in to the mechanic and he changed out the poer pack and all coils - It ran great for a few trips out - but every morning when I would leave the dock it would get up to speed and suddenly bog down and drop RPMs losing speed - after a few seconds it kicked back up to speed and that was it for that trip - it did this almost every trip out - then one trip it bogged down and never kicked back up to speed - so I took it back - we rebuilt all three carbs and changed the fuel pump - and it is still not giving us full power - mechanic is scratching his head and thinks the new power pack may have gone bad already? Any other suggestions -
This motor sat but showed hardly any use plus I have thrown a big chunk of change at it so I dont want to give up now -
I appreciate your help
Brian

Re: 1990 70 HP Evinrude Need Help No power

Take an inductive timing lite and put it on each cyl when it acts up. Look into the timing lite for black spots (like turning a light bulb on and off). You may be able to find out if it's an ign or fuel prob and which cyl is acting up.

Re: 1990 70 HP Evinrude Need Help No power

Check your plug wires... I had a similar problem and one of my plug wires had separated from the boot. This caused it to only run on 3 cylinders intermittently. It still ran, but couldn't even get up on plane.

I ended up bringing the old wire in to a local NAPA and they had a plug wire that matched exactly except for color, big deal. Don't forget dielectric grease if you do have to go this route.

Re: 1990 70 HP Evinrude Need Help No power

Thanks I will check try both -