MerCruiser 140 ok to run in gear on muffs?

[Jacalore]

Troubleshooting a problem where engine stalls when accelerating, but ok in neutral. I need to simulate a load for the engine. Can I run it in gear (1500rpm) without damaging anything?

 

[thumpar]

Re: MerCruiser 140 ok to run in gear on muffs?

Just make sure the drive is down and you will be fine. Make sure no one is around the prop. This will not put a load on the engine though.

 

[Oshkosh1]

Re: MerCruiser 140 ok to run in gear on muffs?

I don't see why not...but watch the RPM's. There won't be much of a usefull "load" on a free spinning prop.

 

[Jacalore]

Re: MerCruiser 140 ok to run in gear on muffs?

Ok, thanks. Any safe way to load the engine without being in the water?

 

[thumpar]

Re: MerCruiser 140 ok to run in gear on muffs?

You can try a big container that will put the prop under water. The water will need to be deep enough for the impeller to be in water though not just to the intakes. It is about half way up.

 

[Jacalore]

Re: MerCruiser 140 ok to run in gear on muffs?

Hmmm... That mat be difficult to arrange. Let me see where I'm at... Running in gear must put some load on the engine, even if it doesn't fully simulate in-water conditions. Hopefully, the fault will show... Thanks for the feedback.

 

[thumpar]

Re: MerCruiser 140 ok to run in gear on muffs?

It would be like jacking up your car and running it in gear. The only "load" would be the friction from the gears which is not much.

 

[Jacalore]

Re: MerCruiser 140 ok to run in gear on muffs?

Ok, I see what you mean. That wouldn't be much of a load. Its never easy, is it?

 

[alldodge]

Re: MerCruiser 140 ok to run in gear on muffs?

Back the trailer in the water and run it

 

[Jacalore]

Re: MerCruiser 140 ok to run in gear on muffs?

The ramp is an hour away. And there's a fee. I've been down there twice recently only to return with the same engine problems. I'm determined to solve this before I go back again. If only I were waterfront, instead in a forest!

 

[NHGuy]

Re: MerCruiser 140 ok to run in gear on muffs?

Why not post what you have observed and see if we can work you through it.

 

[thumpar]

Re: MerCruiser 140 ok to run in gear on muffs?

Get one of those totes for storing stuff at walmart or target. If it is not deep enough to get to the impeller put muffs on it too. All you need is enough to get the prop fully in water to get a load.

 

[Bob_VT]

Re: MerCruiser 140 ok to run in gear on muffs?

Ok, thanks. Any safe way to load the engine without being in the water?

No. That's the short answer and do NOT have the drive tilted or you can do real damage. Even a container as large as a 275 gal fuel tank will not provide enough load.

 

[Jacalore]

Re: MerCruiser 140 ok to run in gear on muffs?

Why not post what you have observed and see if we can work you through it.

Plan to set up fuel pressure gauge to determine if problem is before the engine (air leak, restriction) or other (carb, compression). I'm away today and tomorrow, I'll tackle this on Monday, and hopefully eliminate one half or the other with this test.

Problem is engine stalls while accelerating over 1500rpm. New fuel lines, fittings from tank to (new) fuel pump to (replacement) carb. All new filters.

I should add that I started a separate thread on the stalling problem. And this inquiry was about loading the engine for testing purposes. Thanks for all your advice, I appreciate it.

 

[bonzoscott]

Re: MerCruiser 140 ok to run in gear on muffs?

With out looking at your other threads, You're not going to re-create load on the trailer unless it's backed into a test tank. Replacement carb raises and eyebrow. Is it OEM? Is the fuel pump pumping to spec? Accelerator pump in carb comes to mind. Can you accel slowly to plane? Lot of variables.

 

[Fun Times]

Re: MerCruiser 140 ok to run in gear on muffs?

You can try a big container that will put the prop under water. The water will need to be deep enough for the impeller to be in water though not just to the intakes. It is about half way up.

Though this idea would not put a load on the prop at all, what it will do if not covered is, once he puts it into gear and the propeller makes one rotation, most of all the water inside the container will come rushing out just enough so that the holes in the lower unit will be uncovered almost instantly.

It's pretty cool to watch the water rush out and a quick way to drain the tank/container when you're all done needing it.

For diagnosing purposes, maybe you would like to locate a boat service center in your area that has a prop shaft dyno for testing so that hopefully they could at the very least narrow down the problem for you.

Outboard Motor & Stern Drive Prop-Shaft Dynamometers

Just another suggestion is all, Good luck.

 

[achris]

Re: MerCruiser 140 ok to run in gear on muffs?

In our boat shop we had a 1000 litre tank built especially for this purpose. It also had a lid on it, which was sealed around the edges, and latched down to stop the water blasting the lid up and emptying the tank in 0.36 seconds! Even with a cut-down prop we couldn't put too much power in from the V8s, just too much water moving around... You could see the sides of the tank moving when a decent engine was powered up...

The easiest thing you could do is find a river or creek you could reverse the trailer down into and run from there...

Chris.....

 

[Idodishez]

Re: MerCruiser 140 ok to run in gear on muffs?

No. That's the short answer and do NOT have the drive tilted or you can do real damage. Even a container as large as a 275 gal fuel tank will not provide enough load.

Do damage how? I'm troubleshooting a cooling system issue now and am running it with earmuffs. Is that an issue?

 

[alldodge]

Re: MerCruiser 140 ok to run in gear on muffs?

Do damage how? I'm troubleshooting a cooling system issue now and am running it with earmuffs. Is that an issue?

If the drive is tilted above the trim limit, the u-joints are put in a bind and can be damaged. To high a tilt can also damage the boots, this is why there is a trim limit switch on the outdrive

 

[achris]

Re: MerCruiser 140 ok to run in gear on muffs?

Do damage how? I'm troubleshooting a cooling system issue now and am running it with earmuffs. Is that an issue?

Pleade start your own thread and don't hijack this one.
Read through the 'stickies' and the top of this forum to see how to ask your question to elicit the most answers with the best information....

Chris......