1992 mercruiser 3.0 stalling when shifting into gear and trouble getting up to speed

[Grub54891]

Sound's like you have a choke or carb issue. A sticky choke will cause it to load up-to much fuel-and stall out,or run to rich and have no power due to fuel overload and not enough air. A plugged up carb will seem about the same. On another note,not enough fuel could do it also,plugged filters or weak fuel pump would cause running issues also.

 

[mikwur]

[FONT=&quot]I recently purchased a 1992 Thompson Calae 1800 with a 3.0L Mercruiser. I put it in the water today for the first time and ran into a few issues. The engine will start right up when I give it a little throttle and stays running at a great idle. However, when I pull the throttle back and attempt to put it into gear (forward or reverse) it stalls right out. Starts back up everytime with no problem, but I cannot get it to simply sit at idle without extra throttle or put it into gear without stalling. Second part of the issue is when I attempt to get up on plane, the boat sounds normal (temp, rpms, etc.. all look good) but it simply won't get up and go. The only thing I can compare it to is when your prop is loaded up with weeds and you get a little shake and no speed. Here is what I can see needs some work from a basic inspection:

Prop has some dings - no chunks missing, but pretty substantial
Anode is basically broken of flush
Steering is heavy/sluggish

Everything else looks solid. Last detail is that the boat sat for almost two years (all winterized by a professional). Thanks for the help!

​Mike[/FONT]

 

[Rick Stephens]

Welcome!

That one is pretty easy - the lower shift cable is sticky, probably needs replacing. When you shift there is an electric engine cutout that kills the ignition - hopefully just long enough for the gears to go into or out of engagement. If the lower shift cable is sticky then the engine just dies. There are times you can thoroughly clean and dry a cable and get it working smoothly - it only takes a little grease to make it sticky. But a worn cable housing can allow the cable to get hung up as well. Those you'll have to replace to rid yourself of the problem.

Rick

 

[mikwur]

Thanks for the info! I kept getting an error message when I tried to post, but it must have gone through. Would that impact the boat getting up to speed as well? Thanks again.

 

[Rick Stephens]

No Title

If you're talking about the cable, if it doesn't outright kill your engine it can make it miss a lot. Easy to see, open your engine compartment and look at the interrupter, watch it when you shift a couple times. Easiest to see this when running in the water as it may never even go all the way into gear on muffs. If it isn't dropping back into the valley immediately then it is sticky.

You most likely have a Gen2 Alpha 1, so your switch and linkage may be a bit different. But you get the idea.

 

[Rick Stephens]

And yeah, the forum is all messed up. Someone needs to run database maintenance. Notice you still have zero posts?

 

[Grub54891]

I do agree with the shift problem,that is something to check. If thats it it will do as stated. If that don't resolve it check the carb,and fuel systym.

 

[mikwur]

Would the shift cable impact the boat's ability to get up and get going as well? The boat sounds like an automatic trans. car that is revving up but not going to the next gear. With only two people in the boat, it will get up on plane, but with a few more (still well under the max weight) it won't get up on plane. Thanks for all of the info Rick and Grub. I'll check over that cable today and get it back in the water.

 

[Fishermark]

No - the shift interrupt would have nothing to do with the failure to get on plane. It is designed to cause the engine to momentarily "stumble" when shifting out of gear. It should never be engaged when shifting into gear. If it is, the cable is either bad or is incorrectly adjusted.

Your problem with planing may just be the need for a different prop. What is your WOT (wide open throttle) rpms? If too low then you may need a different prop. There are other causes as well of course. Basic tuneup with compression check would be the first step.

By the way - there is some excellent information at the top of the page in the "stickies" - both on the shift interrupt function and failure to achieve the proper rpms.

 

[thumpar]

Welcome!

That one is pretty easy - the lower shift cable is sticky, probably needs replacing. When you shift there is an electric engine cutout that kills the ignition - hopefully just long enough for the gears to go into or out of engagement. If the lower shift cable is sticky then the engine just dies. There are times you can thoroughly clean and dry a cable and get it working smoothly - it only takes a little grease to make it sticky. But a worn cable housing can allow the cable to get hung up as well. Those you'll have to replace to rid yourself of the problem.

Rick

The shift interrupt is only for coming out of gear. Since it sat for 2 years I would start with a carb rebuild. The part are only around $20 and it is an easy job.