Alpha One stalls coming out of Reverse only

[drun_trucker]

1991 Merc 4.3, alpha 1 gen 1,

shifting and functionality is fine in and out of forward, goes in to reverse fine comes out fine except for stalling.

It seems to me that the shift interrupt is malfunctioning. I just brought the boat home yesterday so I havent done any leg work yet but im leaning that way.

Preliminary suggestions please.

 

[alldodge]

1991 Merc 4.3, alpha 1 gen 1,

shifting and functionality is fine in and out of forward, goes in to reverse fine comes out fine except for stalling.

It seems to me that the shift interrupt is malfunctioning. I just brought the boat home yesterday so I havent done any leg work yet but im leaning that way.

Preliminary suggestions please.

I would start with adjusting the lower shift cable. Look for achris vids in the adults only section (link in my sig). If after adjusting you still have issue, then replace the lower shift cable.

 

[airdvr1227]

While not really a fix I've found that my rig will stall coming out of reverse if I have the drives fully turned to starboard or port. I'm thinking that the binding effect of having them hard over is too much for the motor to overcome.

 

[thumpar]

Since you only have the problem coming out of gear I would suspect that it was the shift interrupt. That is most likely a lower shift cable not adjusted or one that needs replaced.

 

[04fxdwgi]

May be possibly shifting it too slowly, or perhaps the interupter return spring is weak.. The Alphas are meant to be shifted quickly, due to the dog clutch and interupter circuitry. If shifted too slowly, the interupter can kill the engine completely. The Bravo cone clutch eliminated that.

 

[Bondo]

That is most likely a lower shift cable not adjusted or one that needs replaced.

Ayuh,.... Classic symptoms of a failin' lower shift cable that's draggin', internally,...

Usual fix, is replacin' the lower shift cable,....

 

[DaboatnutinWA]

Had the same issue on my 4.3 Merc Alpha last summer......replaced lower shift cable and all is good.

 

[drun_trucker]

Just to give all you guys an update...I personally never verified the stalling issue before asking the question but have since addressed it. The stalling was not a shift cable cable adjustment or anything of that nature.

I would imagine that due to a lack of use and build up of varnish the idle adjustment needed to be turned in.

Upon further investigation I had WAY more problems than just a stalling at idle. Water in the oil is bad. I found that I have a cracked block.

With that said, I am now on the hunt for a new motor. I have mine down to a long block and is ready to be removed from the boat. I have found what seems to be a viable replacement except the potential replacement is 3 years newer.

My current (junk) engine is 1991 4.3L Pre Vortec, my question is can I put in a 1994 4.3L Vortec. The 1994 is a complete drop in ready unit...

Thoughts, suggestions or recommendations please.

 

[Fishermark]

I don't remember what years they changed the various items... but it sounds like the 94 should be a direct fit, drop in replacement. I don't know if there will be exhaust manifold differences or not... but those things can be addressed pretty easily. Is this a marinized engine? If not, you will want to check the core plugs to make sure they are brass. The head gasket should already be composite.

 

[bruceb58]

1994 is actually not a Vortec if you are thinking it has Vortec heads. If this new engine was really a Vortec, it would have different heads and intake manifold. Exhaust manifolds would be the same.

Engines with Vortec heads didn't come out until 1996.

If this was my boat, I would be searching for an engine with Vortec heads.

 

[Bondo]

Ayuh,.... I posted 'bout the motor in yer new thread, 'bout a newer motor,....