76 85 HP Johnson Javelin V4

IASLAB

Cadet
Joined
Feb 23, 2007
Messages
6
The engine has been gone thru by a dealer. All compression is good and supposedly has had a carb rebuilt done to it. My Question? after having the engine warm, when idling down, like going thru the harbor, it will eventually load up and die., Sometimes it starts right away, other times I need to rechoke it and then it starts. Also after idling down, it seems to have a higher idle rpm for a minute or two but the makes a "popping noise" then idles down, it may keep running but sometimes also dies? Any advice? Could it be a fuel line problem, like not keeping enough pressure?
Thanks.
IASLAB
 

Timmstng67

Seaman Apprentice
Joined
Sep 10, 2007
Messages
35
Re: 76 85 HP Johnson Javelin V4

Is it popping back Through the carbs? My 77 140 was popping back through the carbs and it ended up being the reeds. Don't know if this helps but thought I would throw that out there.
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: 76 85 HP Johnson Javelin V4

sounds to me like you've got a cylinder cutting out. That popping noise is most likely it's last gasp before quitting. Check spark first, but you'll probably be attacking the carbs in short order.
 

Relliott

Seaman Apprentice
Joined
May 6, 2008
Messages
34
Re: 76 85 HP Johnson Javelin V4

Sounds like carb issues. They might need to be taken apart again and rebuilt.
 

wavrider

Chief Petty Officer
Joined
Nov 26, 2007
Messages
543
Re: 76 85 HP Johnson Javelin V4

MY 73 85hp was doing the same thing, turned out to be a weak coil, I replaced all 4 at the same time and no more problems, thatis after I went through the carbs three times and was about to attack the reed valves before someone here convinced me it was in the ignition system.

Pull your sparkplug wires and look for rust on the boot connection, they are very bad for corrosion under the spark plug boot, causes high resistance and misfire or "POP" sound.
 

LiLGrady17

Seaman
Joined
May 1, 2008
Messages
67
Re: 76 85 HP Johnson Javelin V4

I'd start by looking at the engine yourself or find someone else to look at it. Being a '76, it's possible the dealer really wants to sell you a late model used or new OB he has. I had it happen to me. Find another service place. If your not into doing your own stuff, an independent mechanic who services first, then may sell used OBs secondly.. Ask your boating friends for a reccomendation.

I'd do the carbs to rule them out, and you'll know for sure they were rebuilt. I had a cylinder missing because it was being flooded with gas. The plug was carbon black. It happened to be the lowest compression cylinder too. Dealer Mech said I should look for new power.
I rebuilt the carbs, cylinder came in, & engine purrs.. Good Luck
 
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