bigfatmatt

Yeah this is my thinking, I stripped the part with the jets in and cleaned that out, took the jets out and cleaned them separately, but might need to strip it down entirely and get it in an ultrasonic cleaner. Prop turns freely yeah.

I ran carb cleaner (the stuff that comes in an aerosol can) through the jet, it was spraying properly out of all of the holes.

Update: - Replaced spark plugs - Replaced fuel filter - Replaced the fuel and added some Redex, emptied all the sediment out of the fuel can - Cleaned the carb & jets with carb cleaner - Cleaned the fuel line out thoroughly Engine will now start and run in neutral or in low revs, if I try to push her to higher revs even warm she cuts out. Thinking I need to find a Yamaha outboard specialist at this point. Thanks for suggestions. Also trying to start with the vent closed she chokes out instantly, there is safe ventilation out of the compartment the tank sits in so fume buildup isn’t a major concern.

Cap of the fuel tank has the air vent open, confirming. I’m going to take another look tomorrow with a mate who knows what he’s doing. Seems like the most likely culprits are fuel line/primer bulb, spark plugs, and jets.

The engine wont start in gear, I did put it in gear in one of the videos to show that it’s happy to fire on gear while fuel is being pushed into it.

The kill switch is a clip below the ignition, if the clip comes off it will kill the engine. There’s not one on the outboard itself.

I’m using Super Unleaded which I believe is E5. I don’t know if the previous owners used E10.

I can get it running with or without throttle but only if we keep manually priming the fuel (10-15s after we stop priming it cuts out), so seems to be an issue with drawing fuel in manually. Video: https://www.veed.io/view/38958e59-7796-4245-8112-ea9283a63dfb?panel=share Fuel tank has an air vent but it was open.

I can’t see a manual choke anywhere on it, the only dial/knob I can see is the dipstick. Anyone know how I could have a hope of identifying it and finding the right manual? Lol

Thanks for all the responses, I did know about the tell tail and that’s working fine, good jet of water streaming out of the back. Fuel is definitely on. There is definitely fuel in the tank which is max 2-3 weeks old. The squishy primer thing goes hard after a few compressions. I’ve let it sit for a bit (assumed I might have flooded it by overpriming last time) and it’s started running (with some weird sounds) for a few minutes before cutting out. Video/audio: https://www.veed.io/view/fbc205a9-c507-4e9d-ac94-2cc81402d2e9?panel=share I’ll try to find a manual and work out where the spark is but posting in case anyone has ideas from the sounds (I know engines talk, I just don’t speak their language yet).

Agree with this 100%. I haven’t cast off yet, I ran the engine last time on the mooring for about 30 minutes a couple of times just to make sure it ran (which, perplexingly, it did) and put some juice back into the starter battery.

I’ve primed it with the squishy primer thing (not sure about terminology). I’ve attached another video with the engine cover removed, I can’t see a spark but I’m not sure where I’d be looking for it (I got this boat 4 weeks ago and I’m completely unfamiliar with internal combustion engines — trying to learn). I don’t think there’s any way water would get into the fuel, the fuel tank has been properly closed and inside the rear under-seating storage which is dry. https://www.veed.io/view/b7fdb2c5-fee0-4d8a-b694-941b4205a87a?panel=share

I’ll preface this post by saying I’m useless with engines. Last came to the boat 2 weeks ago (last week of June), engine ran fine. Most of the petrol was new that week. Came back today and it absolutely doesn’t want to run — siezing up almost immediately. I’ve attached a video, sorry about the shite quality. https://www.veed.io/view/f8649539-96f6-4f41-b5a0-46b4e2e76a9f?panel=share

Thanks, how should I size the starter for a 9.9kW 4 stroke petrol outboard? I assume it doesn’t need a 110Ah battery?

Any recommendation on which LiFePO4 batteries and BMS to look at? Should I also have an AGM to start the outboard and just keep that completely separate?