3 motors all same problem?

[tom2]

I have a 18 foot center console that had a 1986 50 hp Johnson.Boat would get up and go with no problems. When the lower went bad I bought a 1977 50 hp Evinrude this motor did nothing but bog down and wouldn;t plane the boat. Then I bought a 1982 60 Hp Merc same problem. Now I have a 70 1977 Hp Evinrude and still have the same exact problem.I changed props ,cleaned cards,everything else with no inprovement.All this doesn't make sense to me Any one have any ideas?<br />Thanks for the help,Tom

 

[JB]

Re: 3 motors all same problem?

Have you been using the same fuel tank with all of the OMC engines, Tom?<br /><br />One common cause of the bogging you describe is a restricted fuel supply system that can't meet the demands of WOT. Blocked vent, restricted pickup, air leakage in the line.<br /><br />Try a new tank with fresh gas and line (including bulb).<br /><br />Good luck.

 

[Silvertip]

Re: 3 motors all same problem?

The replacement engines are all 20+ years old and I suspect the carbs are gummed/varnished up internally. You said you cleaned them, but cleaning is only effective if carbs are removed, disassembled, every passage and jet cleaned thoroughly, blown out with compressed air, and reassembled with new kits. However, before doing that, any engine performance problem should start with a compression check. A tired engine will not respond to any amount of tuning. Since you have three different engines, you also have three different props. The props on the two replacement engines may be very different than the original. But again, before throwing money at props, get the engine running properly. One last thought, since all engines exhibit the same problem, have you checked the fuel tank pickup, hose, primer bulb, and fittings for blockages. I understand it worked ok for the original engine, but something could have happened during the first repower.