Johnson stalls when engaging gear

Hi Everyone,<br /><br />I have a 3 cylinder 1980 Johnson 70 Seahorse Model Number: J70ELCSA. <br /><br />My problem is that the engine regularly stalls when engaging gear. This happens when setting off (normally when surrounded by many expensive boats in the marina), in both forward and reverse and also when coming along side the marina and selecting reverse to pull the stern in; which usually results in a hard landing!<br /><br />I have had to hold the revs up on the hand throttle and then as I close that, put her into gear to get away.<br /><br />I have now turned the idle up which has worked to a certain extent; but the idle sounds much too high and quite often results in the exhaust boiling the water as the gases leave the hub of the prop. <br /><br />Does anyone have any suggestions???

Re: Johnson stalls when engaging gear

Try cleaning the low speed jets on the carbs...Also check the RPM in gear. It should be around 800 rpm. Also try decarbing the motor...

Re: Johnson stalls when engaging gear

Hi George, welcome to the forums.<br /><br />Is this a new problem? Meaning, have you had the engine for a while and this problem has just occured? <br /><br />When was the last time a tune up was performed on the engine including carb overhaul, ignition testing and compression tests?

Re: Johnson stalls when engaging gear

George,Also insure that the carb linkage roller is on center with the scribe line of the fiber cam when controls are in neutral and "just" touching.

Re: Johnson stalls when engaging gear

Thank you all for your advice...<br /><br />The engine was winterised last October by my local JOHNSON dealer. I didn't recommission the engine until the end of July due to an ever expanding family. <br /><br />The first trip of about 30 - 45 minutes was fine. The second one was different. The engine stalled on slipping the mooring 3 or 4 times. I eventually got it started and put that down to not thoroughly warming the engine up; which with hind sight was not the case.<br /><br />Then a short while later whilst running at speed the revs for a set throttle opening, started to flutuate. <br />I stopped and checked the fuel tank vent. This was open. I then noticed a slick of fuel spreading from the engine apparently from the top exhaust! I was also aware of my blood pressure rapidly increasing!! I made my way back to the marina to investigate/sulk:<br /><br />1/ Upon closer examination I found that the top carb float chamber resevoir drain plug was completely undone - Hence the fuel pouring out and draining down the leg into the sea - not through the exhaust as I first thought!<br /><br />2/ I also wanted to turn the idle up due to the stalling. Note I now use 'we'! We adjusted what we presumed to be the idle screw but I now know this was the carb linkage roller which 'ob' referred to.<br /><br />My question is how would adjusting the carb linkage roller cause the engine to stall like this??

Re: Johnson stalls when engaging gear

The carb link roller is factory set with the cam scribe line .This setting dictates the point at which your carb flaps are opening in relation to the ignition timing.If this setting is off too far it can cause throttle response problems at higher end and lower end of throttle range.<br /><br />Your problem may very well be fouled carburetors.Are you using the recommended Champion sparkplugs?L77JC4 or QL77JC4 gapped at .030".

Re: Johnson stalls when engaging gear

Wow 'ob' that is a prompt response!<br /><br />Okay I will get the carbs, the carb linkage and ignition thoroughly overhauled by my JOHNSON dealer at the end of the season. <br /><br />As far as the spark plugs go they were fitted by the the Johnson dealer and are NGK R but I do not know the exact spec.<br /><br />I do know that I can't afford a new engine and that the Johnson is basically a strong and reliable engine which I will have to spend a little more on this year!!<br /><br />Once again thanks for the advice.<br /><br />George

Re: Johnson stalls when engaging gear

Met128, are you sure 800 rpm idle in gear is right?<br />Just wondering.<br /><br />Thanks, Brad.

Re: Johnson stalls when engaging gear

It's actually 850 in gear on my 70 hp but I've found that the three cylinder loopers operate a bit better if in gear idle is around 900.They don't like being trolled for extended periods.

Re: Johnson stalls when engaging gear

Hi ob<br /><br />I note you talk about your 70 hp. If it is similar to mine I would appreciate any comments positive and negative you care to make about the 70 Seahorse. In particular strengths and weaknesses.<br /><br />George

Re: Johnson stalls when engaging gear

I've owned both the 2 and three cylinder model John/Rudes and my experience with them have all been good.They are a proven design that have stood the test of time ,notwithstanding some quirks that a few later models have had in OMC's closing years.Ive had 83',85', and presently 96' model loopers and liked them all.Weaknesses in my experience have been limited to the fact that the 2 and three cylinder engines require precise idle mix and linkage setting to maintain smoothe idle in gear.

Re: Johnson stalls when engaging gear

Thanks ob<br /><br />What does 'looper' mean?<br /><br />Cheers<br />George

Re: Johnson stalls when engaging gear

Its short for loop charged which is a design porting feature which allows more efficient cylinder scavenging.