Mercruiser stalling every 20mins?

[Javinix]

Hello, my brother just bought a boat with a 185 I\O mercruiser. He was told it runs great for 20 minutes and then shut off like you turn the key off. No sputter, no loss of power, nothing. Can be WOT and it just shuts off. I maybe early on this post as we have a few ideas of things to check, and haven't started yet,but wanted to know what yall thought. The motor was rebuilt last year and ran great until the middle of the summer and started this. Things i have thought to check are the following...ignition switch, started relay, vapor lock and control module. If anyone has any other ideas please let me know as I dont claim to be a mechanic but know enough to be dangerous as they say lol
Thanks for any thoughts or ideas of things to check

 

[alldodge]

Re: Mercruiser stalling every 20mins?

Hello, my brother just bought a boat with a 185 I\O mercruiser. He was told it runs great for 20 minutes and then shut off like you turn the key off. No sputter, no loss of power, nothing. Can be WOT and it just shuts off. I maybe early on this post as we have a few ideas of things to check, and haven't started yet,but wanted to know what yall thought. The motor was rebuilt last year and ran great until the middle of the summer and started this. Things i have thought to check are the following...ignition switch, started relay, vapor lock and control module. If anyone has any other ideas please let me know as I dont claim to be a mechanic but know enough to be dangerous as they say lol
Thanks for any thoughts or ideas of things to check

Your list of things to check is a good start but this is not a vapor lock problem. When it dies can it be started right back up or does it need to cool down? If heat is causing possibility of the coil. Bring along a voltmeter and see if you have 12 volts on the + side of the coil (purple wire).

What is the serial number of the engine preferred, but at least the year?
Has anything been done to engine, points changed to electronic, something else?

 

[Javinix]

Re: Mercruiser stalling every 20mins?

thanks for another idea. I will get the S\N off the motor. Boat is an 86....dang cant remember make. Like I said he just bought it...yesterday, one of those deals you cant pass up even if we cant get fixed, still wont loss $ on resale lol. Guy he got it from said everything was rebuilt\replaced but the coil and distributor....piston, rings, heads all redone, new plugs and wires. Outdrive torn apart and redone. Trailer has new axle, tires, lights.

 

[alldodge]

Re: Mercruiser stalling every 20mins?

thanks for another idea. I will get the S\N off the motor. Boat is an 86....dang cant remember make. Like I said he just bought it...yesterday, one of those deals you cant pass up even if we cant get fixed, still wont loss $ on resale lol. Guy he got it from said everything was rebuilt\replaced but the coil and distributor....piston, rings, heads all redone, new plugs and wires. Outdrive torn apart and redone. Trailer has new axle, tires, lights.

Being an 86 and if it still has the original distributer then need another possibility is the condenser.

When it dies can it be restarted right away or do you have to wait for it to cool down?

 

[180shabah]

Re: Mercruiser stalling every 20mins?

When it dies can it be restarted right away or do you have to wait for it to cool down?

Still waiting....

Also don't forget o check the fuel tank vent...

 

[frantically relaxing]

Re: Mercruiser stalling every 20mins?

If it doesn't have points, it could be the hall-effect trigger switch. I've had 3 triggers go bad in my life so far, 2 of them did exactly what yours is, just goes dead intermittently. Might also be the trigger/switch air-gap needs adjusting...

 

[Javinix]

Re: Mercruiser stalling every 20mins?

Sorry folks I was out of town closing my camp up for the winter. OK I found a model # 01855346 We have yet to fire this thing up at home as I have not had any time to get over to his place. We were talking and my brother said the he was told, yes it does fire after shut down but no power to get going again. The guy put a new floor in it and we were thinking maybe he pinched a fuel\vent line? I'm going to try getting over there tomorrow night if all goes as planned lol. I post my findings after we get it fired and I see for myself.
Thanks again for the thoughts and ideas on what to check on.

 

[Javinix]

Re: Mercruiser stalling every 20mins?

Ok...we ran this thing at the house last night tacked a 2K for 45 mins with no problems, no shut down, no sputter, no over heating, no loss of oil pressure...nothing. The guy said issue at 20mins WOT, which we cant do on the driveway so we are going to try to take it out this weekend if the Pittsburgh weather cooperates with us. I'll keep yall posted.
Thanks again for the thoughts

 

[Javinix]

Re: Mercruiser stalling every 20mins?

We took the boat out on saturday. 1st...brrrrr! 2nd... it did just what the guy said..WOT shuts down like turning the key off, 3\4 throttle same thing, tech at 2 grand runs fine. When it shuts down it starts right back up. We watched the temp, when it stayed at 140 no problems, WOT it goes to 150 and shuts down. Is there a overheat kill switch on this thing somewhere? If your quick enough with the trottle to back it off as it's shutting down it will stay running.
ANY IDEAS?

 

[Bondo]

Re: Mercruiser stalling every 20mins?

We took the boat out on saturday. 1st...brrrrr! 2nd... it did just what the guy said..WOT shuts down like turning the key off, 3\4 throttle same thing, tech at 2 grand runs fine. When it shuts down it starts right back up. We watched the temp, when it stayed at 140 no problems, WOT it goes to 150 and shuts down. Is there a overheat kill switch on this thing somewhere? If your quick enough with the trottle to back it off as it's shutting down it will stay running.
ANY IDEAS?

Nope, no overheat shut down switch,....

Sounds like it's runnin' outa gas,....

When it dies, is there gas available in the carb,..??

When it dies, is there still voltage at the coil's (+) terminal,..??

We know this is an '86, 185 hp,...
Is it a V6,..??

 

[Javinix]

Re: Mercruiser stalling every 20mins?

It is a V6. there is no sputter, no hiccup, nothing at all that suggest it's running out of gas. Has a new fuel pump on it. We thought coil also was a possibility so changed it after we got home. Have to wait on another "warmer" day to test it again.

 

[thumpar]

Re: Mercruiser stalling every 20mins?

You could try it with the gas cap off to see if it is the vent.

 

[Javinix]

Re: Mercruiser stalling every 20mins?

All new gas lines, vent is clear

 

[alldodge]

Re: Mercruiser stalling every 20mins?

It wasn't sounding to much like fuel to me because it just cut off and no kill switch. After much review I'm going to think it is the ignition amplifier. Old model was 390-9355A2 and has been replaced by 15247T02, both of which are more then 400 bucks. There are some threads which discuss similar issues but many indicate it does fine at lower RPM's but when increased it will die. One mentions to check and even replace grounds, others after stalling they unplug/re-plug in the amplifier connector and it will work again. DonS mentions that if it was him and suspected the amplifier he would change over the Delco EST system.

 

[8001sw56]

I have a similar problem with my 1986 Alpha 1. It runs great for 30 min , then just cuts off. If I wait 20 min it starts back up. I'm stumped.

 

[thumpar]

I have a similar problem with my 1986 Alpha 1. It runs great for 30 min , then just cuts off. If I wait 20 min it starts back up. I'm stumped.

You should probably start your own thread but look at my post above as a starting point.

 

[GA_Boater]

I have a similar problem with my 1986 Alpha 1. It runs great for 30 min , then just cuts off. If I wait 20 min it starts back up. I'm stumped.

This thread is almost 2 1/2 years old and very inactive, Look at the Help Tip on top of the page. Then start a new topic with more information for a much better chance of help and getting good advice.

Your Alpha isn't staling after 30 minutes, the motor in front of the Alpha stern drive is stalling. Tell what motor you have in the new topic.

This is closed.