Changing from carb to oil/fuel injection

[cessna 205]

Decision dilemma , I am looking at replacing my 83 mercury 200hp with an oil injected Fuel injected engine.
Is having one and not the other OK?

Is having the oil injection a maintenance or general failure problem?

Is the fuel injection system reliable and is it often a general failure problem?

Other than draining the premix out of the old fuel tank, is there anything I should know about making the transition, as wiring harness, instruments, controls?

My tilt/trim pump in mounted inside the boat, do the newer models have the tilt trim mounted on the motor?

 

[Chris1956]

Re: Changing from carb to oil/fuel injection

Oil injection is very convenient. The quality of these oil injection systems vary over model years and brands. What motor is the replacement?

Standard EFI is simply a better carb. It is very much like throttle body injection that Detroit used for some years. I have never owned a motor with this, but it is widespread, and I think reliable. Do not expect any real change in performance or fuel mileage from a carb model.

The new PTT units are much more compact that the one you have. They work just as well, but do not allow you to trim to any angle, like yours does. That is not usually an issue however. The only drawback that the PTT unit is exposed to the water, and can rust or worse. Keep an eye on it and keep the rust under control.

Controls can be the same, if you choose a Merc as the replacement. The three button PTT control panel will work, or you can get a new control with a toggle switch. Wiring is completely different, but can be adapted. Control cables are interchangeable

 

[cessna 205]

Re: Changing from carb to oil/fuel injection

Chris

thanks, very very helpful info, To answer your question, the possible replacement would be a mercury and is either a 1993 (oil injection only),or 94 oil injected and efi, or a 2001 oil injected and efi.

 

[Chris1956]

Re: Changing from carb to oil/fuel injection

I replaced my '77 Merc 1500 (inline 6) with a '93 Merc 135HPV6. I created a wiring harness connection diagram and butt spliced the old witring harness to the new harness. The controls cables are the same. I connected the three PTT wires to my 3 push button panel. The gas line fitting is different.

 

[AMD Rules]

Re: Changing from carb to oil/fuel injection

.... The new PTT units are much more compact that the one you have. They work just as well, but do not allow you to trim to any angle, like yours does. That is not usually an issue however. ....

Hey Chris... can you elaborate on that statement? I'm not sure I understand what is meant by the 'trim to any angle' comparison. I envision a motor that tilts/trims around a steering tube pivot, to just about any angle required. Just curious what difference you see between old side mount trim rams and the newer integral trim. Are you speaking of a restriction in movement inwards, or trimming in?

 

[Chris1956]

Re: Changing from carb to oil/fuel injection

AMD, The old side mounted rams would trim the motor to any angle and hold under power. The newer 3 ram PTT units trim 20* or so, but will not hold against power when tilter higher than that.

Most boats do not benefit from more trim than the newer PTT units can deliver. Some high performance boats might need more trim.

 

[AMD Rules]

Re: Changing from carb to oil/fuel injection

Thanks.... learned something. I didn't realize my motor wouldn't hold steady on the center ram alone, under power. Then again, like you said I can't imagine ever needing to be under power with THAT much trim