does my timing need adjustment or carb

[livysdaddy]

I am new to I/o boats but am fairly mechanically inclined. I have a '89 omc 210 horizon four winns with a cobra outdrive and 5.7 engine with a rodchester 4bbl carb. I have just redone the top half initally started out as just rebuilding carb but pulled intake to see more about the engine kinda suspected water in oil and was right so I went ahead n pulled heads and had them checked and reworked. Got it all back together last night n started it up. Started very easily ran well but had a miss kinda of at idle(1100 rpm) but once u throttled it up it smoothed out some what but if you really reved it up it would pop through carb a bit and u could hear a miss in the exahust. I changed plugs this morning(champion rv8-c) cap n rotor seemed to be fine. When I put it in gear u could hear a small bit of grinding as it went into gear in both foward and reverse. Is this caused by my idle being too high? What should my neutral idle speed be? As for the small miss and poping would the carb being a little out of adjustment cause this or would timing most likely be the problem? Thanks in advance for any suggestions! If I am going to have A boat I have got to be able to work on it myself!!!!

 

[HT32BSX115]

Re: does my timing need adjustment or carb

Howdy,


And welcome aboard.

A couple of things...

If you had water in the oil, did you pressure check the cooling system before you pulled the heads?

1100 RPM is WAY too high and you WILL damage the clutch dogs if you do not get it back to the correct idle RPM (about 650)

Popping and missing could be ignition. Did you replace the wiring, cap/rotor, points etc?

How much water did you have in the oil? Have you (ever) checked your manifolds and risers/gaskets?


You NEED the correct OEM OMC service manual if you want to be able to successfully work on your engine and drive. (Seloc and Clymer just don't cut it)

The following is good info....... http://www.hastings.org/~stuart/cobra/


Cheers,


Rick

 

[livysdaddy]

Re: does my timing need adjustment or carb

Thanks rick I definitely do need a factory service manuel!! Cap wires and rotor button are my next move. Y'all keep the ideas coming I am new and trying to learn all I can thanks y'all!!!

 

[Bondo]

Re: does my timing need adjustment or carb

Thanks rick I definitely do need a factory service manuel!! Cap wires and rotor button are my next move. Y'all keep the ideas coming I am new and trying to learn all I can thanks y'all!!!

Ayuh,... How 'bout a Compression, 'n leak-down test,..??

Popping through the exhaust sorta says Bad valves...

 

[a70eliminator]

Re: does my timing need adjustment or carb

Having just gone through the heads means the distributor had to be pulled out so yea I would definately look at the ignition timing before anything else, and yes 1100 is double what's recommended and shifting that high can damage your drive.

 

[livysdaddy]

Re: does my timing need adjustment or carb

The 1100 rpm was out of the water on a hose. How much can I expect my rpms to change when I put the boat in the water and put some back pressure on the exahust? Will putting the prop in a tub accomplish the same thing as far as setting idle rpms?

 

[HT32BSX115]

Re: does my timing need adjustment or carb

The 1100 rpm was out of the water on a hose. How much can I expect my rpms to change when I put the boat in the water and put some back pressure on the exahust? Will putting the prop in a tub accomplish the same thing as far as setting idle rpms?

You want 650 RPM in neutral (and it won't change much in the water..... that's why there's idle relief ports in the transom mount......) You get what you get in gear.........which will be slightly lower probably.