runs great outside of water not in it

[bfconstruct]

I have a 1989 5.0 rebuilt entire motor. It runs good on muffs. When I put it in the water it idles for 30sec or so the shuts off and wont restart. It turns over and I have plenty of power. Pulled it out of the water and didnt restart untill we let it set for about 10 mins. The only things that are not new is the exhast. There is a small hairline crack on one of the manifolds. It barely drips water. Any ideas?

 

[Don S]

Re: runs great outside of water not in it

Did you set your timing by ear or with a timing light?

 

[bfconstruct]

Re: runs great outside of water not in it

Timing was just set by ear

 

[bfconstruct]

Re: runs great outside of water not in it

I tried changing the the advance on it when it wouldnt start. No luck till pulled it out of water

 

[Don S]

Re: runs great outside of water not in it

Timing was just set by ear

There's the answer to your problem.

 

[bfconstruct]

Re: runs great outside of water not in it

Ran great last fall with timing the same

 

[Bt Doctur]

Re: runs great outside of water not in it

ear wax build up

If it fuel, spark, or what. you got to narrow it down some more.Next time it stops on the water pull the spark plugs to see if any are wet with water.

 

[bfconstruct]

Re: runs great outside of water not in it

I took apart my exhast to see if there was any obstructions near the shutters. I noticed there one shutter was bigger and could completely seal the tube and one was smaller allowing water to pass by. Is this normal or should they be the same size. And if so which size?

 

[Don S]

Re: runs great outside of water not in it

They should be the same size, but shutters are not causing your starting problem.

 

[bfconstruct]

Re: runs great outside of water not in it

Thank you. I'm taking it in to get timing set perfect and tune carb

 

[Don S]

Re: runs great outside of water not in it

Why don't you buy a timing light, that would be cheaper than paying someone to set it.

 

[bfconstruct]

Re: runs great outside of water not in it

Is there a difference in setting the timing out of water vs in the water under load

 

[dubs283]

Re: runs great outside of water not in it

Is there a difference in setting the timing out of water vs in the water under load

not really, but the timing should definitely be set using a timing light

setting idle speed must be done in the water in gear for most mercruiser applications

 

[bfconstruct]

Re: runs great outside of water not in it

And idle speed is adjusted by the cable?

 

[Don S]

Re: runs great outside of water not in it

Timing is set to 8? BTDC at idle rpm, Between 650-700 rpm.
Disconnect the throttle cable and adjust the idle speed screw on the carb to get in that range of rpm. You may have to adjust as you get the timing close to where it should be. Then adjust the throttle cable so there is a slight preload on the carb linkage toward the idle position. When you go to the water, you may have to adjust the idle rpm and the cable.

 

[bfconstruct]

Re: runs great outside of water not in it

I took the boat out yesterday. Had carb adjusted along with the timing and rpms. Ran good. Now another problem has arised.It shifts in and out of gear out of water but when in the water once in gear its extreamly difficult to get it back in nuteral the same goes for reverse gear. There is a lot of tension on the shifter. Any ideas. I did have the outdrive off last fall to change the gimbal bearing if that makes a difference.

 

[Don S]

Re: runs great outside of water not in it

Now another problem has arised.It shifts in and out of gear out of water but when in the water once in gear its extreamly difficult to get it back in nuteral the same goes for reverse gear. There is a lot of tension on the shifter. Any ideas.

Shift interrupter switch isn't working, or not hooked up correctly after the rebuild.

Read this thread and you will understand the system a bit more, and why it's hard to get out of gear.
HOW TO: How the Shift Interrupt system works?/ 288089

 

[bfconstruct]

Re: runs great outside of water not in it

If its wired correctly and still doesn't work does that mean I need s new switch? Can it be tested with a meter?

 

[Eric 3.7LX Alpha 1]

Re: runs great outside of water not in it

I believe the switch is NLA. You can test it with a meter or by hand while the engine is running. push it off to one side or the other and it should kill the motor by grounding out your spark.

The two wires going to the switch will have continuity when the switch is pushed/moved off center

 

[bfconstruct]

Re: runs great outside of water not in it

Thank you. Ill be out of town for a couple weeks but will check it when I get back. Thank you for your help