Mercruiser engine woes

[badhat]

So I purchased my first boat a while back and had a tough time getting it running. Anyhow, after many days of running it in the driveway on muffs... it was time for me... so I thought... to take it out for a spin. So I load up my boys and we head out to the lake. Sooooo I back on down.. launch it... lower my outdrive... start it up... starts right up.... I let it warm up a few minutes.. time to push off.. my son jumps in... I put it in gear and pushed into reverse... backs up fine... shift it back to neutral and pull it to go forward.. and it dies... never starts again. Of course after all the reading I have done I have nothing that I need to rescue ourselves.. no oars.. nothing.. so we drift for about 2 hours and 20 minutes before we wash up on shore at the other side of the lake.. I tied off the boat to a nearby tree and we walk back to the park. We finally ran into a guy that offered to pull us back... heck of a guy... we were very appreciative that he would do it so willingly. Sorry for the story but some might get a chuckle out of it... What I have is a 1971 boat with a 120hp Mercruiser.. does anyone know what might have gone wrong to cause this to happen? I mean is there something about reverse that to cause it to die and not start again... because I brought it home and it started right up in the driveway.

 

[HT32BSX115]

Re: Mercruiser engine woes

Howdy,


It sounds like the the shift ignition interrupt switch activates when it shouldn't. I think you have a #1 or an MR drive.....There are online manuals here that you can download.

Have a look at the following message. http://forums.iboats.com/showthread.php?t=342393

There's info on how to trouble shoot your shift interrupt system there among other things.


Regards,


Rick

 

[Don S]

Re: Mercruiser engine woes

Sounds to me like your lower shift cable is toast. Happens all the time around this time of year. After the boat has been sitting for months.
Bet when you were running on muffs you never shifted gears, forward and reverse and back to neutral did you?

Have a look up in the Adults ony thread at the top of the page.

 

[lowkee]

Re: Mercruiser engine woes

so we drift for about 2 hours and 20 minutes before we wash up on shore

HAHA! I bet you'll never be without a paddle again. Glad nobody had to do #2 while you were floating for hours . Hope you at least had some bonding time. Maybe a good time for your kids to teach you the boy scout motto

 

[Bondo]

Re: Mercruiser engine woes

Ayuh,...I'd guess the boat's problem is the Lower Shift Cable....
Your problem was a total Lack of a Safety Kit, including the most basic,... Paddle....

 

[achris]

Re: Mercruiser engine woes

Ayuh,...I'd guess the boat's problem is the Lower Shift Cable....
Your problem was a total Lack of a Safety Kit, including the most basic,... Paddle....

or radio, or mobile phone, or flares, or V-sheet..... and the list could go on.... I like Darwin.

Chris......

 

[180shabah]

Re: Mercruiser engine woes

...Or maybe an anchor, could've stayed a little closer to the ramp.

 

[frank246]

Re: Mercruiser engine woes

I put it in gear and pushed into reverse... backs up fine... shift it back to neutral and pull it to go forward.. and it dies... never starts again..

This is odd, now there is your 1st problem (or your seat is backwards)
Did you first pulled (or pushed) the lever back into neutral before starting again, (neutral switch)
Otherwise as stated in above posts a seized lower shift cable.

 

[df909]

Re: Mercruiser engine woes

Hopefully you get the boat running and you and the boys enjoy it. Please make sure you have your safety equipment and everyone knows how to use it, including your boys. If anything happens to you or your situation is taking all of your attention, the boys need to know what to do in an emergency.

I was just at one of our local lake and noticed someone having an engine compartment fire. They didn't know how to put it out and weren't doing anything really to make their potentially deadly situation any better. I was able to help them get their fire out & towed them to the dock. Luckily everything worked out, but not everyone is that lucky. So...not to harp on you but be prepared.

 

[badhat]

Re: Mercruiser engine woes

Oh I forgot to mention that it did turn over just never started again. After tinkering with it quite a bit this morning I am smelling alot of fuel and thinking that maybe the carb is the issue. I did learn my lesson all at once in being over confident. So after I go through everything with a fine toothed comb I will also be buying these other must haves to keep a situation like what happened from happening again.

 

[frank246]

Re: Mercruiser engine woes

Oh I forgot to mention that it did turn over just never started again. After tinkering with it quite a bit this morning I am smelling alot of fuel and thinking that maybe the carb is the issue. .

This is exactly what the shift interruptor does... kill the ignition therefor you smell gass but no spark is added.
Look inside the engine compartment where the shift cable is mounted together with the lower shift cable. There is a lever switch that should be not activated when in neutral, with the roll in the gap, if not this switch grounds the ignition so the engine stalls.
This switch should only be activated when shifting out of gear when on the water.
When the shift cable that runs to the outdrive is stiff or seized the switch is activated when it shouldnt be.
Hope this helps

 

[HT32BSX115]

Re: Mercruiser engine woes

HAHA! I bet you'll never be without a paddle again. Glad nobody had to do #2 while you were floating for hours . Hope you at least had some bonding time. Maybe a good time for your kids to teach you the boy scout motto

Yeah! just be glad you weren't up $hlt creek with no paddle!!!

A corroded/sticky lower shift cable or binding shift mechanism (in the lower unit) will definitely do this whether the boat is in or out of water.....

 

[badhat]

Re: Mercruiser engine woes

This is exactly what the shift interruptor does... kill the ignition therefor you smell gass but no spark is added.
Look inside the engine compartment where the shift cable is mounted together with the lower shift cable. There is a lever switch that should be not activated when in neutral, with the roll in the gap, if not this switch grounds the ignition so the engine stalls.
This switch should only be activated when shifting out of gear when on the water.
When the shift cable that runs to the outdrive is stiff or seized the switch is activated when it shouldnt be.
Hope this helps

Ohhhh.... let me go test this out. That would make alot of sense! Thanks!

 

[bigskiohio]

Re: Mercruiser engine woes

dont forget to run the blowers!!!!!

 

[badhat]

Re: Mercruiser engine woes

Yep been sure to run the blowers prior to starting. In the driveway the interrupter seems fine.. but I am going to keep working it because this must be what happened to me on the water. The boat sat for quite a while before I bought it so I imagine there are going to be a few hiccups here and there.

 

[scutly]

Re: Mercruiser engine woes

In the driveway the interrupter seems fine..

the switch only functions when the prop and drive are under load. ya have to be in the water to test it. the way the gearing works in the drive is that the engine has to momentarily stall at exactly the right time to take the load of the gears so you can shift to neutral. that's what the interrupter switch does in conjunction with the outer part of the shift cable . if its out of adjustment, its killing the engine (grounding the coil) at the wrong time (in your case its the forward shift position) causing no spark and a lot of gas smell if ya keep cranking. hope i explained it properly everything i learned, i learned here!

 

[badhat]

Re: Mercruiser engine woes

the switch only functions when the prop and drive are under load. ya have to be in the water to test it. the way the gearing works in the drive is that the engine has to momentarily stall at exactly the right time to take the load of the gears so you can shift to neutral. that's what the interrupter switch does in conjunction with the outer part of the shift cable . if its out of adjustment, its killing the engine (grounding the coil) at the wrong time (in your case its the forward shift position) causing no spark and a lot of gas smell if ya keep cranking. hope i explained it properly everything i learned, i learned here!

Oh so another trip to the lake.. woohoo!