Re: two vs one
For most people, a main engine and a kicker would be the best solution, if two gasoline engines are desired. Having a trolling motor in place of the kicker can be a very convenient solution too, but it has to be remembered that a trolling motor will pull the boat very slowly and wear a battery down pretty quickly, when run "full bore." As such, this is not a good solution for people who venture far from the ramp.
Mounting a small pair of outboards can have alot of advantages and alot of disadvantages. I used to have a pair of ERude 35hp motors on my current boat and liked the setup alot. This setup is not entirely failsafe, however, because you can damage both engines if you hit something large. Even a large gill net can take out both clutch dogs (been there done that, have the T-shirt) and leave you dead in the water.
I don't necessarily subscribe to the theory that a matched set of outboards requires more maintenance than a single main powerplant and a kicker. In either case, two engines have to be maintained. That said, there may be a fair argument in terms of the cost of maintaining the two larger engines. There is also a higher cost in terms of gas and oil consumption. That issue is most of the reason why I removed my Rudes and went to a single Johnson 65hp, with a Johnson 6hp as a kicker.
One distinct advantage of the main engine/kicker combination, is that the kicker spends most of each trip tilted up, so it isn't likely to be damaged. That leaves the operator with a pretty reliable backup situation.
One caution, however - it gets very easy to neglect a kicker. I always try to run mine for at least a few minutes on each trip. I also try to make sure that it is run under load, in both forward and reverse gears, rather than just letting it idle at the dock. I don't always have time to do this, but I try to do it most of the time.
Even if you do this, you can fall victim to letting maintenance items go for too long. I maintain my own motors, but fell victim to this recently. I pulled my kicker off of my boat a couple of weeks ago to deal with a sticking gearshift handle, and then found myself fixing a number of other things.
I finally just decided that it was time to go through each system to do some housecleaning and rebuilding. I'm glad that I did, because I found alot of stuff wrong. By the time I am done, I will have disassembled the entire motor, with the exception of the powerhead and gearbox. All other components will have been cleaned, regreased and repainted in some cases. I will also have rebuilt the water pump (worked on that tonight), the fuel pump and the carburetor. I run aftermarket electronic triggers in this motor in place of points/condensors, so the ignition should be fine.
The best advice that I think we can offer is to consider all of the options presented here and then decide which fits your situation the best.
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