'90 225 OMC Stalls Under Load

[EastEnder]

This is an update from a thread I had before.....

My stbd motor now stalls when in gear. I can get it to crank, start, idle (fast) put it into gear and it just putters out. I tried several times, and it just quits. It will still rev out of gear, but it doesnt sound right.....it sounds choked i think....the noise it similar to when you open the throttles without advancing the spark. I havent gotten a compression test done yet. This is also a motor that had a lower compression on one cylinder that had its timing adjusted to compensate for the lack of compression.

Any thoughts? Did I blow that one cylinder? I'll post compression results when I get them...it was a rainy, nasty day in the NE today....

 

[tashasdaddy]

Re: '90 225 OMC Stalls Under Load

without compression numbers don't do anything.

 

[CharlieB]

Re: '90 225 OMC Stalls Under Load

As you pull the plugs to do the comp test look at them carefully. a perforated diaphragm in your fuel pump will flood one cyl and foul the plug repeatedly and give you the operating symtoms you complain of.

Pull the vacuum hose off the fuel pump and check for gasoline in the hose.

If yes, order a fuel pump, if no, I'm all wet, repost your compression #'s

 

[EastEnder]

Re: '90 225 OMC Stalls Under Load

I just did a quick compression check and only got about 75 to 80 psi on 4 out of the 6 cylinders.....the other two were about 60psi....can that be? I was using an older compression guage that doesnt screw into the head, you just hold it in place....do I have a bad guage?

 

[HighTrim]

Re: '90 225 OMC Stalls Under Load

all gauges read differently, the main thing is the difference between cylinders. Were the bottom 2 the low ones by chance?? Try a decarb to see if that evens things out.

 

[CharlieB]

Re: '90 225 OMC Stalls Under Load

J&E made a number of lower compression engines, I don't remember the years.

Your guage may also be a bit off.

What you are looking for is the amount of difference between cyl's

Auto-Zone loans tools with a deposit, other stores/shops may also, ask and re-test.

How do the plugs look?

Did you check the vacuum hose to the fuel pump?

 

[EastEnder]

Re: '90 225 OMC Stalls Under Load

When you say decarb you mean, inside the cylinders correct? Two of the cylinders were definately different than the rest....If your looking at the spark plug end of the engine, it was the middle left and the upper right cylinders that were lower.

As for the vacuum hoses...i dunno where the fuel pump is or whats a vacuum hose and whats a water, or fuel hose. Is the fuel pump right next to the VRO pump?

I started her today out of the water to winterize her, and it was a rough start....she would crank, then hit a rough spot and stop....I thought it was the battery, so i gave it a boost with the battery charger on the "engine start" function, and it fired up. It even idled good, better than it did in the water....i didnt need to raise the idle speed at all. Could this be due to lack of backpressure on the exhaust?


Thanks again for all of your help.

-Tom

 

[dajohnson53]

Re: '90 225 OMC Stalls Under Load

When you say decarb you mean, inside the cylinders correct? Two of the cylinders were definately different than the rest....If your looking at the spark plug end of the engine, it was the middle left and the upper right cylinders that were lower.

As for the vacuum hoses...i dunno where the fuel pump is or whats a vacuum hose and whats a water, or fuel hose. Is the fuel pump right next to the VRO pump?

I started her today out of the water to winterize her, and it was a rough start....she would crank, then hit a rough spot and stop....I thought it was the battery, so i gave it a boost with the battery charger on the "engine start" function, and it fired up. It even idled good, better than it did in the water....i didnt need to raise the idle speed at all. Could this be due to lack of backpressure on the exhaust?


Thanks again for all of your help.

-Tom

"Decarb" means use a solvent to remove carbon buildup from the pistons and rings. The technique is described in a FAQ and is pretty easy.

The fuel pump IS the "vro pump". The VRO (or OMS) pump is a two portioned pump, one part pumps gasoline, the other pumps oil which mixes in the gas. One single pump unit. You can learn about it here:
http://continuouswave.com/whaler/reference/VRO.html

Back pressure indeed affects idle. When in the water, the exhaust has to push against the water to exit the engine, therefore causing a load that the engine has to push against. It is standard procedure to adjust the idle higher than normal on the hose so it will be normal in the water. That's probably why you're seeing better idle on the hose. Good luck.

 

[EastEnder]

Re: '90 225 OMC Stalls Under Load

Thanks again for the help. I'll save this info for the spring, when I get a chance to look at her again. Thanks again all.