Inline Fuel Pressure Gauge

[wttmrwolf]

Hi Folks,

I have a 1996 Evinrude 115HP with only 140 hours on the clock. The damn thing stalls after its been idling for about 30 seconds. If I fast idle or get underway I don't have any issues.

The mechanic is suggesting I replace the fuel pump but since its a VRO model it will be a costly experiment.

I'm thinking of putting a fuel pressure gauge inline to see if the pump is creating enough pressure before I replace the fuel pump. I'm worried it could be a simple air leak.

Can anyone point me to where I can purchase a fuel pressure gauge that I can put inline to test the back pressure?

I found a few pressure gauges but they aren't inline.

Any tips welcome. Thanks

Mrwolf

[a boat]

Hi Folks,

I have a 1996 Evinrude 115HP with only 140 hours on the clock. The damn thing stalls after its been idling for about 30 seconds. If I fast idle or get underway I don't have any issues.

The mechanic is suggesting I replace the fuel pump but since its a VRO model it will be a costly experiment.

I'm thinking of putting a fuel pressure gauge inline to see if the pump is creating enough pressure before I replace the fuel pump. I'm worried it could be a simple air leak.

Can anyone point me to where I can purchase a fuel pressure gauge that I can put inline to test the back pressure?

I found a few pressure gauges but they aren't inline.

Any tips welcome. Thanks

Mrwolf

Hi, why does the mechanic not have a fuel pressure gauge that he can put in line and test the fuel system, very easy to do-instead sounds like another untrained guy just guessing saying to replace the fuel pump. Easy to bench test the VRO or correctly the OMS with a pressure and vaccum gauge. Does it go fine above idle, if so I doubt the pump will be at fault?

From what you are saying, it sounds like a simple mixture (air:Fuel) problem and by removing the air box cover you can adjust the idle mixture screws if they or you have the correct tools. If the engine is a touch too lean it will "sneeze" and stall and it takes about 5 minutes to make right. I would be looking for another place or get yourself a genuine manual and not that hard to do yourself.

Cheers,

Huey.

[wttmrwolf]

From what you are saying, it sounds like a simple mixture (air:Fuel) problem and by removing the air box cover you can adjust the idle mixture screws if they or you have the correct tools. If the engine is a touch too lean it will "sneeze" and stall and it takes about 5 minutes to make right. I would be looking for another place or get yourself a genuine manual and not that hard to do yourself.

Funny you say that. I just ordered a service manual since I figured its worth getting to know how to service outboards myself. I figured an inline pressure gauge could be one of the first tools to put in my arsenal.

You mentioned a vacuum gauge. Any idea where I can start buying some of these specialised tools?

Mr Wolf.

[a boat]

Funny you say that. I just ordered a service manual since I figured its worth getting to know how to service outboards myself. I figured an inline pressure gauge could be one of the first tools to put in my arsenal.

You mentioned a vacuum gauge. Any idea where I can start buying some of these specialised tools?

Mr Wolf.

Hi Mr Wolf, we use genuine OMC (now BRP) vaccum and pressure gauges to test gearboxes and VROs-we have had them over 20 years. They are expensive and you will see there is part numbers for them in your manual when you get it. For a home tech I would not be saying to rush out and buy these, but an in line fuel pressure gauge are not that dear from Repco or the like and worth having. Are you seeing fuel starvation problems above idle?

Cheers,

Huey.

[wttmrwolf]

Hi Mr Wolf, we use genuine OMC (now BRP) vaccum and pressure gauges to test gearboxes and VROs-we have had them over 20 years. They are expensive and you will see there is part numbers for them in your manual when you get it. For a home tech I would not be saying to rush out and buy these, but an in line fuel pressure gauge are not that dear from Repco or the like and worth having. Are you seeing fuel starvation problems above idle?

I was concerned the service parts could be costly. Repco is a great idea, thanks. Since you asked about the actual problem here is a more detailed description. Maybe you can point me in the general direction or at least tell me what the problem is not.

So to start at the beginning.

Evinrude 115HP 2 stroke 1996 - 97 140 hours on the clock. Well maintained, all cylinders have been compression checked and tested fine. Full service with impeller housing replaced due to some mild corrosion, fuel line and bulb replaced to try and resolve stalling issues.

Prior to the most recent service I started having problems.

Symptoms - would not keep running after initial startup. Followed standard start routine, 1/4 turn of key, hold in 8 seconds, then full turn. After 5 seconds motor would blow lots of white smoke, shake and stall. It was possible after a few attempts to get it idling for 30 seconds before stall. Fuel bulb would go soft, if the engine was revved in idle it would increase in speed then just loose power and stall. Eventually got it running after about 10 minutes and 20 attempts. Reving the shit out it seems to clear the engine and it would start to run smoothly. If the engine was warm no problem starting and at speed ran at 100%. If allowed to cool problems starting and keeping running returned.

After service.

Mechanice from BRP replaced fuel lines and bulb. Tuned engine and did basic scheduled service. Told me if I was still having problems the fuel pump might need replacing. Not sure if problem starting was air leak, rich oil mix or pump. On startup no smoke anymore. Starts first go everytime. However only runs for 30 seconds if not put in gear or reved. Bulb needs 1 pump by hand to get hard again. Only stalls when idling hot or cold. At higher throttles runs perfectly. Seems to be a slightly different problem to last time or at least the smoking has stopped. Maybe there were 2 problems and 1 has been fixed. Still sounds rough when idling. To the untrained it looks like not all cylinders are firing.

That kind of sums it all up. I must say it seems to start every single time now, even cold, I just need to get it in gear and underway quickly. I'd be very interested to hear what your opinion is on this issue.

[a boat]

Hi, for a start your starting procedure is wrong. Pushing the ket in and holding for 8 seconds will do nothing. Every time you push the key in the choke primer richens the fuel mixture, holding it in does nothing. On cold starts with your engine, you want to prime the bulb till it goes hard, turn key on and push the key in once and crank, when the engine fires you can rev up with the cold start lever, but with your engine it has "quickstart" and it advances the timing until the engine reaches temp (hopefully someone has checked the thermostats and the engine is reaching correct temp).

If the engine runs fine above idle as I have mentioend the fuel pump will be fine. If you have a faulty pump the engine will not get enough fuel at all RPM. Not sure what you mean mechanic from BRP-possibly someone who has worked for BRP. As mentioned it saounds just like a basic mixture issue and your engine is an easy engine to work on, if you know what is going on.

Try using good oil like XD-100 and the smoke will be greatly reduced and hopefully this trained tech has checked and made sure no air leaks into the fuel system, because that causes an aerated fuel mix in the OMS and casues the oil ratio to rise and therefore produce more smoke, especially if using cheap oil.

Best thing to do mate is swing by one day and use the boat at the Hawkesbury and I can show you how to start her.

Cheers,

Huey.

[wttmrwolf]

Hi, for a start your starting procedure is wrong. Pushing the ket in and holding for 8 seconds will do nothing. Every time you push the key in the choke primer richens the fuel mixture, holding it in does nothing. On cold starts with your engine, you want to prime the bulb till it goes hard, turn key on and push the key in once and crank, when the engine fires you can rev up with the cold start lever, but with your engine it has "quickstart" and it advances the timing until the engine reaches temp (hopefully someone has checked the thermostats and the engine is reaching correct temp).

Hi Huey,

I might have to pay you for your time if we can catch up on the Hawksbury. Thanks for the offer. So let me quickly get one thing straight. You say that I don't have the start proceedure correct.

I was told to turn the key 1/4 turn. Wait for the 4 engine checks to complete (lights go off and beep sounds). Push in the key for 8 seconds then turn the key the remaining 1/4 turn. After engine starts release key and in theory engine will keep running. The mechanic told me the 8 seconds press in richens the fuel mix essentially the same as a choke. Maybe my start proceedure is flooding the engine???

You said to push the key in once and crank - Do I turn the key 1/4 turn then push in? How long do I push the key in for?

Rev up with the cold start lever - do I put the engine in neutral and push the throttle forward to increase the revs? Assuming the "quickstart" doesn't do its job

Honestly it sounds like I need you to check it out but I want to give it one more shot this weekend. Hoping to get out on the water and enjoy the sunhine with my kids.

Thanks again.

BEn

[IWANNABROCK]

push the key in once which give's a shot of fuel to richen start up. turn key and crank motor.

[a boat]

+1 to what Jewy said. If you hold the key in for 8 or 80 seconds it does nothing and I guess another case of a "mechanic" telling someone the wrong thing. I guess this is the same guy that told you you had a faulty pump and to replace it when I am betting it will be just a mixture adjustment and easy fix. Just to confirm it does run fine up on the plane because I can not see where you have confimred this.

If you come to work, it is easy to start on flusher and adjust, no real need to go to the water.

Cheers,

Huey.

[wttmrwolf]

Problem solved! I thought you might like to hear why the engine was stalling.

So I bought the engine service manual. Read all the troubleshooting guides in the electrical and fuel system chapters. Started to develop a theory that is was something to do with the electrical timing being slightly off.

Checked the spark plugs and they looked fine. Compared the spark plug serial against the suggest spark plug in the service manual.

WTF!!!!

Wrong spark plugs. Mechanic put plugs that had a tiny difference in the gap.

Replaced plugs with EXACT model suggested in service manual. Started first go and never stalled.

I was mighty pissed but just thankful it didn't damage the engine.

[a boat]

Thanks for the update and well done. Yes the right plug in any engine makes the world of differnece. We see it alot and your engine does need to run the QL78YC plugs that it was designed for.

Also do yourself a favour and run either XD-50 or xD-100 in her and you will be amazed at the difference if you are using "cheap" oil at present.

Cheers,

Huey.

[wttmrwolf]

Thanks for the update and well done. Yes the right plug in any engine makes the world of differnece. We see it alot and your engine does need to run the QL78YC plugs that it was designed for.

Also do yourself a favour and run either XD-50 or xD-100 in her and you will be amazed at the difference if you are using "cheap" oil at present.

Cheers,

Huey.

I have been running XD-50 for the last 2 oil top ups. Definately makes a lot of difference. I think the plug our mechanic installed was QL76YC and I switched them out for the QL78YC. Minute difference but enough to cause the stalling issues.

Yay!