Mercruiser 165 hp Inline 6 PROBLEMS ??

[pennyboating]

I have a 165 hp inline 6 by mercruiser, its about a 1978 model, great motor, will start on the first try everytime. The problem with it is that ever since I burnt the points on it, it has never ran the same. I replaced the points and I am pretty sure they are set correctly ?? When I give the motor throttle it revs up and begins to go but when the throttle gets almost half way to the max it stays the same push and sound. Its kinda like an old outboard that never switches over to the high speed jets. It just gets up to the point and as you give it more gas then it stays the same as far as power but just sucks more gas as you give it more throttle, without producing more push or horsepower. I have tried to diagnose this myself for the last year but just cant figure it out. Now the boat has turned into a slow pleasure boat to just cruise at idle, I WANT TO GO FAST. The compression in every cylinder is anywhere from 131-145 which is good, I think. I rebult the carb, changed the dist. cap, and put an electric fuel pump on it, and I have changed the points a few times. Please help with any advice that you have, the summer is comming quickly.

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

165s L-6s do not break down! lol Welcome to Iboats and Happy Easter. I'm a L-6 owner too. I'd check the dwell and maybe try a coil it may have weakend the coil. Were you running the elec. fuel pump when the points burnt or was that added at the same time you replaced the points. Whats the fuel pump pressure rating?

 

[pennyboating]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

The points burnt while running the elec fuel pump, i just put that on there b/c it was much cheaper than buying a real mercruiser fuel pump, the fuel pump gasket was leaking gas into the block. Anyway, whats the dwell? I should try the coil, can I put an automotive coil on it or does it have to be a marine one?

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

I'm not sure on the coil "good question" someone else may know that. I wouldnt want to tell you the wrong info. A dwell meter can be hooked to your engine and tells you if your points are set within the limits. I just thought of another posability. Check your advance in the distributer. It may be stuck. Do you have a manual? You need one.

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

The dwell on that should be 31-34 degrees I believe.

 

[Don S]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

The problem with it is that ever since I burnt the points on it, it has never ran the same. I replaced the points and I am pretty sure they are set correctly

How did you set the points? Dwell meter? After you get the points set, you also need to reset the timing.
What is the max rpm you can get out of it? Will it go above that rpm in neutral.
Reason I ask, is some point sets require a C shaped spring behind the copper strip. If it isn't in there, then the points won't work after about 1500 to 1800 rpm. Neutral or under load.
If the pump burned up your points, where did you pick up the power for the pump from. Not the coil I hope. Or that could be part of your problem.
Also, with the pump installation, is it installed thru an oil pressure switch so it won't run when the engine isn't running and the key is on? That is very dangerous if it is like that.

 

[pennyboating]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

Do you think it would be a good idea to put an electronic conversion kit in place of the points?

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

The weights and springs under the plate were your points are is the dist. advance, make sure their not stuck or broken springs. Be patient more experienced people than i will be here to help also.

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

Yes, Most people do. I havent yet but i think i'm going to. there will be more people on here giving you opinions on that as well. But before you do that you need to figure out the problem at hand first.

 

[Don S]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

Find the cause of your problems BEFORE switching over to electronic ignition. Or you burn it up to, and they cost a lot more than the points when you burn em up.

 

[starsnstripers]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

Good point Don depends how the pump is wired. And is there a difference between marine and auto coils? they sure look the same. Curious Thanks

 

[Fishermark]

Re: Mercruiser 165 hp Inline 6 PROBLEMS ??

An automotive coil will work fine. Just make sure to get the right one - one with either an internal or external resistor.