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Hello. I have a rebuilt 90hp Johnson Oceanrunner (1998) on my Montauk 17. Bought the motor rebuilt from a reputable shop about 4 years ago and it has run well until the end of last season when it would stall out at very slow speeds and in reverse - making docking a little tricky! Then, when I got that fixed (mostly water in gas), it now stalls out just as the boat begins to plane. It slowly loses power at about 2000 RPM and stops. New gas, new hoses, water separator, etc already done. I trust my mechanic to be honest, but I don't know if he knows as much as he thinks he knows! I don't mind spending the money to get it fixed, but I hate to spend money on somebody making guesses. The engine starts right up again and goes fine at slow/trolling speeds. After market generic controls that came with boat, if that makes a difference.

Thoughts?

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Have an assistant squeeze the bulb steadily and continuously when you try to get onto a plane. If that works, you'll want to look into the fuel pump.

Tim

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I just had this problem on my Johnson. Tedious is right: fuel pump could be problem. I would check your vent line first though- There may be a kink in the line or blockage somewhere. Also, check your fuel water separator- it may need to be changed. Good Luck! Bricken

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Also clean/replace all filters. A partly clogged filter can allow enough fuel to pass to run slowly but as you accelerate the carb bowls began to empty because there isn't enough fuel getting past the filter to replenish them.

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Although he indicates the water separator has been replaced, there's probably a filter internal to the motor too - if that has not been replaced, it could well be the issue. Still, the bulb test is easy (and free) so it would make sense to try it first.

Tim

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Well, they say the carbs just needed a thorough cleaning. Time will tell! I'll keep ya posted! Thanks for the intel.

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Older model outboard motors do not have the advanced filters of today's engines.

As a matter of principle I would run a 10 micron water separator and a fuel stabilizer year round. One may also consider a tank or two of fuel treatment (OEM products like ring-free etc.)

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Well, ran great when I picked her up, as well as the following weekend. But....back at the marina this morning. Same thing: no problems at trolling speed pulling out of the canal, but stalls at anything faster. Did try the bulb trick mentioned above, but to no avail. I see where this is going: I'll give these guys another try, then move to a different marina/mechanic, then another, then repower. A switch here, a thing there, etc. and Ill probably be 15% into a new worry free Yamaha with a warranty.

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Having the carbs cleaned, or doing it yourself, is not unreasonable after 4 years, especially if you've encountered bad gas at some point.

How long do you go between uses of the boat? Do you use a fuel stabilizer?

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You got crap in your carbs. I know you said you replaced fuel lines but that crap is coming from somewhere, and everything south of the carbs needs to be checked. Oh, and pull the carbs and do a proper rebuild.

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Thanks all - I'll politely mention the above to the boatyard. I do use a stabilizer, and weather permitting I use the boat about 1 hour a week of solid running ( I seldom fish or anchor). On this occasion I used it 3 times within a week, with the 3rd time being when the problem struck again about 10 minutes away from dock

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With that usage pattern, and assuming you have the 24 gallon tank, I'm guessing you go through a tank every 2 or 3 weeks, so there's no real reason to be using a stabilizer. Sure sounds like the high speed jet on one or more carbs is plugged. Simple fix if you can find the right mechanic!

Good luck.

Tim

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Thanks all. Could water in the cylinders be a possible explanation?

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No. "Water in the cylinders" is not a problem that outboard motors have - unless you have capsized, in which case this is probably the least of your worries.

More seriously, if a mechanic is suggesting that as a cause - run away!

Tim

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In fairness to him, the conversation had more to do with the gaskets and then, subsequently, water in the cylinders. Not knowing what the hell he was talking about I did two things: 1. posted here, and 2. did a Google search and I did find a thread on another site that dealt with a 90 hp Johnson Ocean Runner stalling (albeit at idle) and water in one of his cylinders. That thread became overly technical for my comprehension. Don't know if etiquette permits me to share the link.

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You can certainly have a head gasket leak which would cause cooling water to get into a cylinder. That would happen to only one of them, though - and I don't think that would affect your idle all that much, but rather your ability to get onto a plane. Did you get the carbs rebuild yet?

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Tedious, thanks. Actually, planing is the problem - the stall at idle was the subject of the thread I found - I was just pleased with myself that I found something out there that might be somewhat on-point! The carbs were cleaned, but not rebuilt since the engine was rebuilt by an Evinrude dealer 4 yrs ago (maybe, 75 hrs of usage since then). The suggestion of the day is to have the gaskets replaced.