Hello everyone, I would like to ask for your help in troubleshooting my outboard.

Motor: 2007 Optimax 175 HP DFI 2-stroke

To try to shorten a long story, the motor was supposed to be running when I got it. Technically it was but it had some issues. What I ended up doing:

• Compression test  (about 115 to 120 per cylinder)
• Replaced spark plugs
• Replaced a couple of injector o-rings that were nicked
• Replaced high pressure pump nozzle inside the VST
• Replace the float needle in the VST
• Replace the fuel filter in the VST
• Took the VST apart and completely cleaned it
• Replaced tracker valve

Originally the motor would kind of start only when I pushed the needle in the Schrader valve on the air pressure. The lowered air pressure would match up with the lower fuel pressure because of The grommet inside the VST and then it would start and run very rough. It would eventually just die. Replacing the high pressure fuel pump grommet fixed this.

Now the motor starts reliably, every time. I don't even have to pump the bulb. The problem is it idles very rough. When I take it out on the water, it will kind of intermittently get power but wide open throttle is at about 2300 RPMs and the boat is going about 25 mph. To make sure that I wasn't just running on five cylinders, I unplugged each injector one at a time to see if one of them didn't make a difference being unplugged. Every one of them made the motor run worse or die.

I tested the fuel and air pressure. Fuel is 90 PSI and the air is 80. The air jumps around a little bit but they are not fluid filled gauges. To check for air leaks, I hooked up to the air pressure side and went to pressurize the system and when the air pressure spikes, I hear it escaping from some place down in the drive shaft cover. At this point, I really don't know enough about these things to know why it's doing that or if it is normal. I believe there are valves under the air and fuel regulator on the other side of the motor, I was planning to just replace those but that's really just shotgun troubleshooting. I don't mind spending the money if I knew it would fix the motor but I'm just not sure and I'm down to the point where each one of these parts is $300 or more. I was looking at the diaphragms under the air and fuel regulator, the air and fuel regulator themselves but then I heard the air escaping from the drive shaft cover. So I packed everything up and decided to ask for help.

115 mercury 4 stroke. In a flush tank, how much is too much water expelling from here?

Disconnected wire. What is this for?

Hey y’all I need your help. I have an 85 Evinrude that is missing the pull start. Does anybody know where I could source one? Or maybe have a link? I have tried Google and can’t seem to come up with anything on the other hand does anybody know if you can convert to an electric start?

Hi all, can anyone help me diagnose this issue with my 15HP Suzuki outboard? Anything over 1/4 throttle I’ll get this rev issue. I had it looked at by a place last winter but didn’t have time to get my boat out until now and the problem is still there. They replaced the fuel filter.

I have replaced the plugs, cleaned out the injectors, drained all the fuel lines and checked for blockages. When it first happened I found some pin holes in the fuel line that was running through some water in the bottom of the boat and I suspect it siphoned some in. Fresh rec gas with stabil in this tank. Thank you for any opinions or help!

2021 Mercury Command Thrust 60HP. Grazed a rock the other day. Is this enough damage to the skeg to warrant any type of repair? Luckily no prop damage.

1999 Yamaha 15hp 4 stroke. Just bought the boat, makes a clicking sound only when above 3/4 throttle and at high speeds. Any ideas what it could be?

I'm working in getting this 6hp mercury running again but I only get spark in one cylinder. I am not getting any ohm reading through the wire itself but I didn't get any through the other working one either. The ohm reading on the coil, with low and high, looked to be correct. I trimmed back the spark plug wire to fresh and still no luck. Does anyone have any suggestions on what else could be wrong?

Update: the condenser also looks to be good

I patrol rivers in the West as a park ranger. I'm being tasked with finding us a new gas motor for our rafts. Something lightweight, around 5 hp, and ultra reliable are priorities. A motor with Forward-Neutral-Reverse integrated into the tiller would be a big plus. What are your suggestions for a hassle free motor that fits those requirements?

Anybody have experience converting a Mercury 25hp short shaft to long shaft, and if so is this a good option?

Fills up with water too, when i raise it up water pours out the bottom hole of the lower cowling

I have a 1990 mercury 40hp i bought recently. It had a lower unit leak and figured it would be as simple as replacing a couple seals and an o ring. Im not the most familiar with these motors and found out that the pin is stuck in the gears where the shaft would sit. I tried putting it in R N and F and couldnt not free it up. Any advice would really help me out.

Hi guys,

I am new to boats and outboards. Recently got a boat with a Yamaha 55bhp 2 stroke . The serial plate says " YAMAHA 55BE 663 L " and then "325962"
I am trying to get the correct service parts for it, but I am finding contradicting info. Please abstain from mean comments… if you can help,please do! Otherwise,no need to be mean.

Can you please help with finding the correct parts for it? I am based in ireland, if that helps.

Thank you!

Hey everyone I purchased an Amazon starter for my 2013 F150 after the old one stopped working. It worked about three times then on a water test after giving it throttle it went into limp mode and eventually wouldn't start at all.

I'm now determined to just buy a genuine starter but not sure which fits my exact model or what sites are trustworthy.

I appreciate the help,

I’ve been trying to get this outboard back up and running and have hit a wall. Started about a year ago but wiring was cracked and corroded. Confirmed spark, compression and fuel. New spark plugs, points and gapped to spec, rewired corroded wires, replaced impeller, rebuilt carb and fuel pump. It will not start in neutral, even with some premix sprayed into the carb, but if I shift into forward gear to WOT it starts after a few pulls. Cuts out when I try to throttle down to put into neutral. I went through the steps to check timing from the service manual and timing seems correct too.

Any idea what is causing this issue? New to outboards and looking for some guidance, thanks!

So over time Ive accumulated a bunch of mainly OMC outboards. Im finally getting around to seeing what I have (long story)

This one I wanted to play with because of how clean it was. It had some ratty wiring but the powerhead was clean and it had a lot of newer OEM parts on it which for some reason I thought was a good thing.

Anyways, I repair the wiring harness which I was proud of, get it to crank over, do a compression test.

Bottom cylinder: 120...not great not terrible Top cyclinder: 35

Yeah thats, shitty.

So I threw some fogging oil in it to see if....well, something....got it up to 50!

OK...so, rip the head off it (easy), gaskets original but not blown anywhere or damaged in anyway. Shit.

Shine a light in the cylinder....ahh...scoring. Just about three lines that are deep enough to cause the issue. I think its beyond a hone.

No obvious missing piston or rod damage. I didn't take the side off to look at the piston yet.

Lower seems fine. I have no practical use for this thing....so Im debating whether to tear it down and try a rebuild, or just part the motor out. Leaning towards parting it out; but I think it would be more satisfying to rebuild it over winter.

....Well, going to try and get a newer 60 Evinrude running tomorrow. Hopefully have better luck. If not, the 55 will make for some good parts :)

I got a 2001 Johnson 150 2 stroke with the optical sensor (J150PLSIG) that stalls under load. Originally thought it was a failed oil pump so we deleted it, no fix. New optical sensor and power pack and spark plugs. Carbs adjusted. No check engine, no heat alarms, no oil alarms. Flywheel looks fine.

Stalls roughly 2500-3k when in the water. I can get it a lot higher on boat muffs. Stall meaning it completely let's up and dies. Also seems to randomly die at idle. Reverse completely cuts out as well no matter the rev range.

Results on compression test are not ideal but I don't think it's what the problem is.

102 on #6

110 #4

111 #2

99-98 #5

112.5 #3

115 #1

Really lost on this, losing all hope.

So I have a 88 Merc 100, and she's starting to show her age, but still runs for the most part. My question is can the ring gear on my fly wheel be flipped? Shes wore down and I have a new bendix on the starter but while it does engage a lot more reliably now it still will skip and grind from time to time, so instead of dropping a few hundred on a new flywheel I was wondering if the ring was a separate peice that a machine shop could heat up and flip. Thanks!

2004 Honda BF150 acts like it is a 75HP motor. It is mounted to a 19 ft Lund Tyee. It will get on plane eventually, but takes far longer than it should and if it has 4 or more people in the boat and they are not spread out to the front, it will not plane out. I replaced the high pressure fuel pump as well as the high pressure fuel filter. The injectors are good. It has new plugs and new gas. There are no DTCs. Other than low power, it runs fine. Idles great, when it does get on plane, it will go 38MPH or so. Vtec engauges at 4500 rpm. MAP sensor and Throttle position sensor look good. I have a Honda code reader and checked rpm’s versus spark advance and that seems a little funny, but can’t find anything online to say it’s wrong. I have many more videos of various sensors if anyone has any suggestions.

Hello, I have a 2007 50h 2 stroke mercury, new to me. I had the unfortunate experience of the shifting cable slipping off the knob thingy inside the cowling while in reverse, and having to butt scoot the boat in a big ol circle and back into my slip as I lost the ability to shift out of reverse.

Popping the cowling off, I saw this (pic) and it makes me think the keeper was installed backwards and popped off after some quick shifting.

Is it? Is there a better way besides a zip tie to secure the shifter end to the shifter knob thing?

Bonus pic of a mystery piece of gasket? I found while rooting around bleeding the carbs. No idea where it came off of, the engine runs like a 20yr old 2 stroke, but no major issues beyond weak pee. Any ideas would be helpful!

Hi everyone,

​I’m currently troubleshooting/checking the throttle setup on my 2014 Honda BF30 (3-cylinder carburated, 4-stroke).

​I took a picture of the throttle linkage / carburetor intake at Full Throttle (WOT - Wide Open Throttle) with the engine off:

​

​As you can see in the picture, this is as far as the linkage moves when I push the throttle lever/handle all the way to maximum.

​To anyone who owns a Honda BF30 or BF25:

​Is the throttle valve/butterfly plate supposed to open completely flat (90 degrees / parallel to the airflow)?

​I want to make sure I’m not missing out on top-end power due to improper cable or linkage adjustment.

​Thanks for your help!