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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16213
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Bogging down once on place, *plane, 1989 Yamaha 225 Excel

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Bogging down once on place
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: *plane
JA: Is there anything else the Marine Mechanic should be aware of?
Customer: 1989 Yamaha 225 Excel

H​ello my name is ***** ***** am I speaking with? I read what you wrote. What kind of history does this engine have? Have you ever personally seen it run correctly? Have you done any kind of troubleshooting on your own yet? Do you have a specific model number for the outboard?

Customer: replied 1 month ago.
My name is***** is a 1989 Yamaha 225 Excell, ran great for a few days then starting having issues with bogging down. I found whoever changed the fuel pumps didn't have the gasket clocked correctly on one of the pumps so it wasn't working. I replaced both the pumps with new Sierra ones. Still had same issue, changed fuel/water separator and used an external fuel tank, same issue. Changed all the coil packs, still same issue.

Hi JR. When did it run great exactly? Are we talking 2 weeks ago or 4 years ago? Do you have a time frame? Do you also have an exact model number on the outboard? Have you checked things like compression, spark output, and fuel pressures?

Customer: replied 1 month ago.
It las ran good a few weeks ago. Compression is about 120psi on all 6 cylinders, i have a spark tester from autozone that shows I'm getting spark on each cylinder, I'm not sure how I could test fuel pressure. I am looking for a picture of the model number but if I remember correctly the decal was mostly worn off.

What kind of spark tester do you have specifically? Do you have access to a timing light? (they are only 20 bucks)

Customer: replied 1 month ago.
Found a better picture of the model #
Customer: replied 1 month ago.
I have a old school timing light
Customer: replied 1 month ago.
It's just odd that it runs fine until I get up to about 3800 RPM and then dies. I give it a few minutes and it runs good, gets up on plane, then dies again. Carbs are clean, took the bowls off and they were spotless.

S​o it's getting to 3800 rpm and then stalling, is that correct?

Customer: replied 1 month ago.

G​ot it. That is a sign of fuel starvation. I saw that you wrote that you ran in off of a different fuel tank. Did you hook that tank up directly to the engine, with new fuel line? Or did you disconnect the fuel line from the boats fuel tank, and hook up a portable tank to that existing fuel line?

Customer: replied 1 month ago.
Disconnected the line from the tank to the input of the fuel bulb. Ran a new line from the fuel bulb to an external tank. Wonder if it is something as dumb as a bad check valve in the fuel bulb?

Did you try hooking up the fuel line directly to the engines fuel pumps, bypassing all other plumbing between the fuel pumps and the fuel tank? Also, have you checked the engine compression yet?

Customer: replied 1 month ago.
No, I will try a new fuel bulb tomorrow and also connect the line straight to the engine if needed. Compression is between 118 and 120 on each cylinder. Did you see the model # in that picture?
Customer: replied 1 month ago.
I took a video of it bogging out tonight if that helps I can try to upload it.

Y​es I did get the model. You can also skip any kind of spark test because that would not fit your symptoms. If the engine is simply getting up to a certain RPM (in your case 3800) and stalling, what is happening is the fuel is not making it from the fuel tank to the carbs. Where you would to start is by hooking a fuel line up directly to the fuel pumps, and sticking the other end of that fuel line into a portable fuel tank. When the engine runs everything on the inlet side of the fuel pumps is under a vacuum. When there is any kind of leak, what happens is air will leak into the fuel stream, and you would not notice that leak as any kind of external fuel drip. In most cases what the issue is, is a leaking fuel line, a leaking fitting, a leaking fuel filter, ect. And those leaks are allowing air to enter the fuel stream. Since it's easier to suck air instead of sucking fuel up, What happens is the fuel pumps suck air in through those leaks instead of sucking fuel up from the tank, and the engine ultimately starves for fuel and stalls out from lack of fuel. Does that all make sense. I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

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Thanks in advance, and good luck

Jason and other Boat Specialists are ready to help you
Customer: replied 1 month ago.
I will do what you suggested Friday as I have plans tomorrow night. I will let you know the results. I uploaded the video to youtube, here's the link
Customer: replied 1 month ago.
Tried the gas tank with line directly to fuel pump, ran the same. Tested resistance of stator. between the blue and black/red wires it should have between 65 and 130 ohms. Mine tested 24 ohms, thinking it's the issue. Thoughts?

Hi JR, good morning. I got the video. Did you ever hook up a fuel pressure gauge between the pump and carbs to see if it had fuel pressure? Where are you getting the specs for the stator, do you have the factory service manual on the engine?

Customer: replied 30 days ago.
No, I don't have a gauge but I can get one if needed. Found specs online, see attached image.
Customer: replied 30 days ago.
This will be here today.

When you got that stator reading. Did you disconnect those blue and black/red wires from the terminal strip and stick your volt meter on the wires themselves. Or did you just touch the meter leads to the terminal strip?

Customer: replied 30 days ago.
Both, read the same.

How does brown to red read?

Customer: replied 30 days ago.
1024 ohms, all other combinations were around 360 ohms.

The stator is what they call a 2 speed stator. It has a high and low speed. The low speed side is the brown to red, the high speed side is those other wise. Typically when the high speed side isnt' working (and yours does read out of spec) the engine will run up to roughly 3000 to 3500 rpms just fine, but it won't go any faster than that. A failed high speed side of the stator also will not cause stalling. It's definitely possible there is more than 1 thing wrong wit the engine, but the stator wouldn't cause the stalling like that. You definitely want to check the fuel pressure to make sure the fuel pumps are good first, before touching that stator.

Customer: replied 30 days ago.
Okay, it has always been a struggle to get it over 3200 rpm. I'll check the fuel pressure between the pumps and the carbs also. I also have access to a used stator that tests within spec for $50. I already pulled the flywheel and stator off yesterday so I will test the fuel pressure with the replacement stator installed.

Sounds good. Let me know how you make out.

Customer: replied 30 days ago.
I will. Thx. By the way, both the fuel pumps are new. I took the previous ones off to inspect the back side for leaking gas and found one had no gasket and the other gasket was clocked wrong. I thought for sure the new pumps and gaskets I installed were going to fix the issue but didn't. Look at the picture attached.

There is more than 1 thing that can cause low fuel pressure other than the pumps. But first we have to see what the pressure actually is. And if that pressure is holding when the engine bogs, or see if that pressure drops about 10 seconds before the engine starts to bog.

Customer: replied 30 days ago.

Keep me posted.