ender_x
19.06.2021 7:17:08
The 4cyl are not known to carbon up the exhaust system, unlike some of its 3cyl cousins. I doubt thats your issue.
See full version: Clogged exhaust port
The 4cyl are not known to carbon up the exhaust system, unlike some of its 3cyl cousins. I doubt thats your issue.
A bit more info on the symptoms you're experiencing may help us get to the root cause of your motor's troubles. ed more
Sounds fuel related. Clean the carbs.
Silly question, but what makes you think that your exhaust ports might be clogged. This is not exactly a common problem.
Do let you friend tinker with it if he don't have a manual or you will wind up in worse shape than you are here
HI,
I don`t have that particular problem.I`m only asking this because someone else`s outboard was acting up and he claimed this was the problem so I figured I`d look for exhaust port in the manual but couldn`t find anything on it.However I do have problems to resolve with my outboard.
My 1997 oil injected 40 hp 4cyl Mariner is hard to start and stalls when I try to accellerate after putting it in gear.It does pick up a bit when I choke the carbs.I`ve just installed a new stater du to an electrical problem that ocured mid summer past.I was thinking gas problem but a friend wantsto check the tyming.Do you have any suggestions?
Idle Air Control Valve (IAC) – Function – Failure Symptoms – Testing
Sometimes the engine stalling will happen on its own while other times; increasing the load on the engine, will cause it to stall. For example, if you turn on your heater or air conditioner; when you have a bad idle air control valve (IAC); then your engine will probably stall immediately afterward. Consequently, the steering wheel might also feel, like it’s being dragged to one side too. more
One common problem is a buildup of carbon or fuel varnish deposits, in the idle speed control valve. The cure for this condition is to clean the valve, with some aerosol throttle cleaner or engine top cleaner. here
So, the idle mixture (percentages of air and fuel) are controlled by FIXED idle jet(s), idle bypass(es), idle restrictor(s), and the idle air-bleed(s). The amount of mixture is controlled by the idle mixture screw. more
What the idle mixture screw does NOT do
The fixed values for the idle jet, bypass, restrictor, and air-bleed were engineered for a set of engine conditions which probably no longer exist anywhere. The composition of fuel has changed (even if ethanol is not present, other compounds are present which change the atomization characteristics of the fuel), carburetors are migrated from one application to another, enthusiasts modify engines (changing the camshaft duration has one of the more dramatic effects on the idle circuit). These changes can cause either an erratic idle, or a dead spot upon acceleration (often misdiagnosed as a defective accelerator pump). Often, the enthusiast tries to adjust the mixture by adjusting the idle mixture screw for more volume (which does give more fuel, but also more air). Generally, the idle circuit will need to be modified (at least on an original equipment carburetor, maybe not so on an aftermarket unit) for best performance. [links]
The typical idle circuit on many modern downdraft carburetors will consist of: (A) an idle jet, (B) the idle bypass, (C) the idle restrictor, (D) the idle air-bleed, (E) the idle passage/port, and (F) the idle mixture screw. Additionally, SOME carburetors may have an addition idle air bypass built into the throttle body (often a measured hole in the throttle plate). more