My engine keeps stalling Whilst at Idle!

P

Puzzled look

Seaman Apprentice
Joined
Jun 3, 2009
Messages
36
I have a 90hp Johnson V4 2 stroke engine on my rib. I have recently bought the rib so am new to this type of engine.
I not sure of an exact age but its around late 1990's early 2000. I think it was new with the boat which is a 2000 model.

When I bought the boat the engine had just been serviced so I'm not sure why it wont idle. I suspect that the revs just need turning up a bit.
The engine controls have a Small lever next to the throttle lever this is what you use when starting the engine. It starts fine and ticks over but when you close the lever to engage gear with the throttle it stalls.

You can (if your quick) close the lever and engage forward gear with the throttle and the engine labours in to life but as I'm sure you will agree this is far from Ideal. Has any one any ideas to trouble shoot?

I can post a photo of the engine if required but this will take me a while as the boat is kept at a holiday cottage.

Many thanks
 
G

glengold

Petty Officer 1st Class
Joined
Feb 24, 2010
Messages
310
Re: My engine keeps stalling Whilst at Idle!

Few things to check, when the motor is trimmed all the way down there is back pressure created by the water. Sometimes motor's are mounted too low, creating additional back pressure. Does it happen on the hose, out of the water? Idle could be set too low. Lastly, or if its been sitting for awhile, firstly: clean the carbs.
 
B

bigrockets

Seaman
Joined
Jul 12, 2010
Messages
63
Re: My engine keeps stalling Whilst at Idle!

Having gone through this on a newly acquired boat I can offer you the following to get you the best advice on the forum. Read the sectet file at the top of this forum. Post the engine model number and serial number from the ID plate on the motor. Has the motor been sitting for a while? Did you run it with fresh fuel or is there stale fuel in the tank. Start with simple things first. Idle adjustments are not as simple as turning a screw. The idle system also controls the ignition timing when you go from neutral to forward. The usual culprit is dirty carbs related to fuel gumming and contaminants. Getting the OEM service manual is the most important and cost effective thing you can do with a newly acquired motor. Get the factory manual, Seloc and the others aren't very good. I ended up rebuilding my carbs and replacing all of the fuel lines from the internal tank to the ones on the motor. I also installed a water separating fuel filter. Give the experts on here the best information you can gather and do the homework assignment and you will get great answers.
 
P

Puzzled look

Seaman Apprentice
Joined
Jun 3, 2009
Messages
36
Re: My engine keeps stalling Whilst at Idle!

Thanks Folks Ill have a go at the carb first, I managed to fix a similar problem with my mercury 20 which had a carb full of junk, I just wanted to make sure there wasn't a magical cure with this engine as its new to me and has controls at the helm.

Im interested in what Glengold said about back pressure as the engine did indeed idle whilst on the hose how ever when I flushed it out the following day is just stalled again. Any one any Ideas?

Also on the throttle housing next to the ignition key there is a Knob which turns has any one any Idea what this might be could this be a throttle adjustment?

Ill start to track down service manuals and look into a carb kit, as I said the engine had been serviced just before I bought it but as to what level Im not sure.

I also gave the engine a good run last weekend at least 6 hours flat out over 3 days (its as sweet as a nut except for idle!)

Ill see if I can get engine and model numbers for the experts.

Thanks for your help so far any other ideas would be appreciated.
 
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