Engine stalls when put in gearMy boat is a 1979 27 ft Carver Monterey Mercruiser 228 305 4barrel - Alpha Drive The engine stalls when shifting gear

[Brock96]

My boat is a 1979 27 ft Carver Monterey Mercruiser 228 305 4barrel - Alpha Drive

The engine stalls when shifting gears

Last year the boat engine would stall going forward and reverse I had to jack up the Idle to prevent it from stalling The boat was only taken out a couple of times
This year the engine still stalls and jacking up the Idle does not work.

With engine running I manually push the Y shift plate (barrel is in the middle) the button on the Shift Interrupt Switch is compressed- engine stalls -

With engine off and the shifter is put in both forward and reverse the shift plate moves and the Shift Interrupt Switch button is compressed

With the engine running the shifter is put in forward the shifter plate barley moves and the SIS button is barley touch- engine stalls - when put in reverse the plate moves and the barrel presses the SIS button -engine stalls

Disconnected the lower shift cable and manually pushed and pulled the cable - it is smooth but a little stiff. There is no history of having any difficulties shifting in and out gears (except for stalling)

Engine will not heat up - thermostat was tested - Exhaust manifolds and the thermostat housing are lukewarm
Intake Manifold is cold - choke does open (submitted a separate Post)

Your help is greatly appreciated

 

[nola mike]

My boat is a 1979 27 ft Carver Monterey Mercruiser 228 305 4barrel - Alpha Drive

Unless you upgraded your running gear, you don't have an alpha--likely an MC-1

Disconnected the lower shift cable and manually pushed and pulled the cable - it is smooth but a little stiff. There is no history of having any difficulties shifting in and out gears (except for stalling)

The SIS should only activate coming out of gear when on the water running. "A little stiff" is a bad cable. There should be practically no resistance

 

[Rick Stephens]

Replace the lower shift cable. It is a wear item. As it ages the inner cable wears into the outer sheathing, that's what causes added drag and actuates the shift interrupt.

 

[Bondo]

Ayuh,..... Welcome Aboard,...... As noted, you need a new lower shift cable,.....

Unless it's just been done, All of the rubber parts in yer transom assembly should be replaced, along with the cable,.....

 

[achris]

Don't go increasing the idle speed to mask a problem like this. Quickest way to destroy your drive.

Chris...

 

[j cat]

My boat is a 1979 27 ft Carver Monterey Mercruiser 228 305 4barrel - Alpha Drive

The engine stalls when shifting gears

Last year the boat engine would stall going forward and reverse I had to jack up the Idle to prevent it from stalling The boat was only taken out a couple of times
This year the engine still stalls and jacking up the Idle does not work.

With engine running I manually push the Y shift plate (barrel is in the middle) the button on the Shift Interrupt Switch is compressed- engine stalls -

With engine off and the shifter is put in both forward and reverse the shift plate moves and the Shift Interrupt Switch button is compressed

With the engine running the shifter is put in forward the shifter plate barley moves and the SIS button is barley touch- engine stalls - when put in reverse the plate moves and the barrel presses the SIS button -engine stalls

Disconnected the lower shift cable and manually pushed and pulled the cable - it is smooth but a little stiff. There is no history of having any difficulties shifting in and out gears (except for stalling)

my 1978 MC470 eng/alpha 1 I adjusted the shift cable to the switch .. then I lube the switches ...what I did the switch took longer to shut down the engine ...I fixed it 25yrs ago .. still working..

 

[achris]

my 1978 MC470 eng/alpha 1 I adjusted the shift cable to the switch .. then I lube the switches ...what I did the switch took longer to shut down the engine ...I fixed it 25yrs ago .. still working..

No, this is the WRONG way to do it. You adjust the CABLE to the drive, then the switch should be ok. NEVER adjust the switch to mask a cable problem, adjustment or otherwise. As I said before, quickest way to destroy a drive... And j cat, I know you're going to say 'mine has been work for 25 years'... You have a 4 cylinder engine, not enough torque to do any serious damage, but the OP has a V8, that does have...

Chris....

 

[Brock96]

Thanks - I now able to shift in an out of gear but only with a high idle and a bang - Sometimes the engine stalls. The engine will not heat up - tried with 2 - 140 temp thermostats -which were tested in boiling water. (confused) The carb is in need of a rebuilt. With the engine running in this condition and with the load of shifting into gear can it cause an engine stall. One of my questions is and I have asked many marine technicians and been on line for hours why this engine will not heat up - no success

 

[Scott Danforth]

Thanks - I now able to shift in an out of gear but only with a high idle and a bang - Sometimes the engine stalls. The engine will not heat up - tried with 2 - 140 temp thermostats -which were tested in boiling water. (confused) The carb is in need of a rebuilt. With the engine running in this condition and with the load of shifting into gear can it cause an engine stall. One of my questions is and I have asked many marine technicians and been on line for hours why this engine will not heat up - no success

you are going to blow up your drive. replace your lower shift cable, adjust the cable correctly and get the RPM's down to below 650 in the water

my guess is your thermostat and housing has an issue

 

[Rick Stephens]

you are going to blow up your drive. replace your lower shift cable, adjust the cable correctly and get the RPM's down to below 650 in the water

my guess is your thermostat and housing has an issue

As stated, replace lower shift cable.

Is possible your temp gauge isn't working right?

 

[achris]

Thanks - I now able to shift in an out of gear but only with a high idle and a bang - Sometimes the engine stalls.

Put the shifter in FORWARD. Remove the drive.

Check that the drive itself isn't causing stiffness in the shift system by moving the intermediate shift shaft into neutral and reverse and back to forward. If the dogs aren't aligned to allow the full movement, turn the prop slightly.

If that passes muster, move to the upper shift shaft. Check by rotating the shift slide out of the way and then rotating the shift shaft. Should be smooth and have very little resistance.

Disconnect the cable from the shift plate and jump down and move the slide in and out. It should be smooth and have very little resistance.

Until you remove the drive and do those three checks, asking here is a moot.

The only thing you can check that doesn't involve removing the drive, is the spring behind the V-slotted lever.

Chris........

 

[Bt Doctur]

Some people never learn untill they break something and then complain.
Shift cables are wear items. When the start to go bad the shift interrupt will activate stalling the motor. You dont compensate ,increase idle or anything else that stupid, you replace the shift cable..
The shift interrupt ONLY activates in forward, IN THE WATER , COMING OUT OF GEAR ONLY any other time is a bad/severly mis-adjusted cable

 

[achris]

Some people never learn untill they break something and then complain.
Shift cables are wear items. When the start to go bad the shift interrupt will activate stalling the motor. You dont compensate ,increase idle or anything else that stupid, you replace the shift cable..
The shift interrupt ONLY activates in forward, IN THE WATER , COMING OUT OF GEAR ONLY any other time is a bad/severly mis-adjusted cable

It does (should) also activate when coming out of REVERSE (in the water)... Never, ever going into gear (either forward or reverse) or at anytime while on the trailer running with flushers.

But completely agree with you @Bt Doctur , OP needs to fix the problem, not try to mask it.

Chris.....

 

[QBhoy]

Good advice above, to be fair...but I would also say that the reason for a low idle, if nothing has been messed with, would usually be crap fuel or a compromised top end, like low compression or water ingress...or again, water in fuel getting in there/or messing up the carb.
I might also suggest that unless your outdrive has been changed since the boat was new, it likely isn't an alpha gen one...more likely would be an MC. I had a 79 boat with a Mercrusier 140 3.0 and an MC1 drive.