Engine stalls going in gear

[SteveL56]

New to boating and to this forum, any advice is appreciated.

I have a 1976 Grew 164 with a 170HP intercooled Mercruiser. The boat sat for several years but is generally in good shape, I know its history and previous owners and know it was well maintained. After working through some problems this summer the one that remains is that after the motor is warm it stalls going from neutral into gear, it will also stall at idle either in neutral or in gear. One time while tubing and the motor working hard it would not go into neutral but other than that one time it will go into neutral but have to get to 2000 RPM right away to keep from stalling. When warm and in gear it will not run at idle, keep the revs above 2000 and it will run all day, lots of power getting on plane. When I go into neutral when warm then back into gear I can hear it engage but then sputters and dies. When the motor is cold everything works fine, no problem at idle in gear or neutral and no problem going from neutral to gear.

Wondering if there are any ideas out there, I am not a mechanic or even a weekend mechanic. It would seem if it was a carb problem it would run bad all the time, not just when warm but I am not sure. I have also been reading about the interrupter switch and wondering if this might have something to do with it, although it seems that effects going from gear to neutral.

The river is almost frozen here on the east coast of Canada so I have the winter to figure this out, any ideas would be great.

Steve

 

[Bondo]

Ayuh,..... Welcome Aboard,...... My best guess is, the lower shift cable is draggin', 'n needs to be replaced,.....

That's what causes the motor to die, when shiftin' into gear,....

After the lower shift cable is replaced, 'n if it still won't idle in gear, or at 650/ 750 rpms,....
I'd rebuild the carb,.....
I say that because if it idles cold, the choke is on, when warm, the choke is off, 'n it might be too lean to idle,....

 

[savetexomabeaches]

Clean carb first, just remove fuel intake line and spray the crud out of it with carb cleaner, and down the throat. Let it sit a bit, crank it up. Check filters.. If that doesn't help, lower shift cable may be dragging and needs replaced.

 

[Rick Stephens]

Not to be argumentative, but I don't consider spraying carb cleaner down the carb to be a useful exercise. Best to roll your sleeves up and do a proper rebuild. That is a pretty simple carburetor they installed on the 470. Following the cleaning instructions is not hard, just painstaking. If doing it yourself is not in the cards, then you'll have to find a mechanic who is skilled at that task. Doing it right the first time is most important, especially with a motor that is going to sit for months without a chance to fire it off and check your work. Check and replace your fuel filters while you are at it. Plugged up filters can cause all sorts of problems.

I would also do a tune up. Burned points or plugs would account for some of your idle problems.

Replacing the lower shift cable is like a rite of passage for Mercruiser owners.

 

[tank1949]

Older Alpha drives have an electrical interrupt switch on the shifter linkage which is usually installed on the stb side of a motor. Adjusting ones that are in GOOD condition can be problematic. Defective ones can cause you nightmares!!!!!!!!!!!!!!!!!!! You can bypass the switch connected to linkage to determine if it is causing the stalls, but keep in mind that these switches cause electrical interrupts to take the torque off your OD when motor/ODs shifts. You will need a friend to push throttle all the way forward and then reverse while you are examining linkage in you OD (you will be upside down looking at your lower unit). Alphas have about a 45% span from neutral to foreword and 45% span from natural to reverse.
The electrical switch can be defective or not be manually adjusted correctly to pop back.
If OD adjustment arc is perfect and motors still stall with switch disconnected, you have another problem. Good luck!

 

[Bt Doctur]

The boat sat for several years but is generally in good shape, I know its history and previous owners and know it was well maintained

Except for the time is sat idle. was the drive ever removed for service before you ran it.Were the cables checked for free operation. did it get a full tuneup. how old is the gas. did you drain and refill or just add good gas to very bad gas.

one that remains is that after the motor is warm it stalls going from neutral into gear

a sign of a sticking ,gummy, corroded shift cable/mechanism


but have to get to 2000 RPM right away to keep from stalling

Clogged ,gummed up idle circuits

Fix these and it will run and shift perfectly.

 

[SteveL56]

Thanks for the suggestions, unfortunately it is in storage and shrink wrapped so will have to wait for spring. I did add good gas to bad and suffered the effects, replaced the fuel filters twice, added a fuel/water separator. I also replaced the points and had the starter rebuilt which seemed to fix the other problems I was having( except lack of experience in a shallow river totaling two ruined props and a bent prop shaft!)

Before I put it away I did have a mechanic do a complete servicing, removed the drive, changed the oil and gear oil etc. I know the previous owner stored it at a marine shop and had it serviced there but I don't know what they did for servicing. I will get the carb rebuilt and shift cable checked in the spring.

I have heard this is not a very good or dependable motor, any thoughts on this or common problems with this motor? Is the closed loop cooling a common problem on older motors?

 

[Bt Doctur]

On the contrary ,its a very good motor producing a lot of HP for a 4 banger.It does however have some flaws. It DOES NOT LIKE TO BE EVEN SLIGHTLY OVERHEATED. You should not try to charge a dead battery by jump starting, the regulator will not like it.The A/F circulation systems will need seal replacement
not a hard job. With a 4 barrel you could get 180 hp out of it.

 

[stonyloam]

Yeah the Dr is right, you should replace the impeller in the outdrive before you use it in the spring, and every other year thereafter. Watch for a leak from the weep hole on the lower starboard side of the water pump, that will indicate the camshaft seals need replacing. DO NOT try to stop the leak by plugging the weep hole. When you get a chance, do a compression check to make sure the head gasket is in good shape. If the voltage regulator fails, you can replace it with an alternator kit.

 

[harleyman1975]

Old gas, vaccum leak, flooding carb (needle and seat, incorrect float level). Just some things that can cause it to run bad at low rpm's.

 

[SteveL56]

There didn't seem to be any overheating problems, it comes up to temperature and the gauge shows normal all the time. I will check the impeller in the spring.

Any fairly easy way to check for a vaccum leak?

 

[Rick Stephens]

Any fairly easy way to check for a vaccum leak?

With the engine at idle you can spray carb cleaner around suspect areas and see if the motor speeds up.

 

[harleyman1975]

it would be leaking at the carb base or where intake mfld joins cyl head...or could be a burned or sticking valve.

 

[SteveL56]

I took it out today for the first time this year and had the exact same problems,I was hoping the service last year might solve some problems. For the first 20 minutes no problems, if it stays in gear and revs above 1500 no problems but put it in neutral it stalls going into gear. It then had a hard time starting but when it did would not go into gear, eventually it would not start and the paddles came out. Brought it home and started no problem in the driveway. I am having a hard time understanding why if the lower shift cable is dragging why it works fine when cold, can anyone explain why this would happen? It seems rebuilding the carb should be the next thing to, and check for a vaccum leak, any other suggestions or ideas?

It is an old boat and not worth dumping much money into, maybe time for an upgrade.

Thanks for the help.

 

[nola mike]

Shift cable can do funny things. Easy enough to check, just watch as you put it in gear. You can see if the switch closes for more than a moment. But sounds more like the carb. May be getting enough fuel with the choke closed.

 

[Bondo]

Shift cable can do funny things. Easy enough to check, just watch as you put it in gear. You can see if the switch closes for more than a moment.

Nope,.... The shift switch shouldn't move at All, goin' into gear,....

Only when comin' Outa gear, 'n only with the boat In the water,....

Any other times, the shift switch shouldn't move, at All,....

 

[nola mike]

Nope,.... The shift switch shouldn't move at All, goin' into gear,....

Only when comin' Outa gear, 'n only with the boat In the water,....

Any other times, the shift switch shouldn't move, at All,....

Right. Shouldn't move. If it's stalling though, and the switch is the issue, you'll see it sticking. If the cable is sticky, it can trip the switch going into or out of gear.