Evinrude e70 PL4 year 1999 working just with 3 spark plugs not wit 4

[MartinBrac]

Evinrude e70 PL4 year 1999 working just with 3 spark plugs not wit 4










I have an Evinrude e70 PL4 year 1999 outboard motor. And it won't fire up. It is just firing up with 3 spark plugs, one plug hole must be open to starting the engine. If I insert all the spark plugs into the engine, the engine will not fire up (second video).




How to fix this, what to check?







VIDEOS:

The motor is working with just 3 spark plugs:

https://photos.app.goo.gl/nyDDPqqFv5y9U2wj7




The motor is not working with 4 spark plugs:

https://photos.app.goo.gl/tL5AB2Mk3LjLzpDN6







Spark plugs are new. Spark is on all plugs (when I pout out the spark and try to fire up). The pump is working. Fuel injectors are clean.




I have a check engine alarm with code MAP sensor 2 (second video), but I think this is not the reason. I have this MAP sensor 2 problem earlier and it was working.




Any ideas of what to do?

 

[webbd]

From your videos, I can see that your engine is a 4-cycle with an overhead cam. I'm not educated on this engine, but have some knowledge and experience. Others on the forum can probably give much better advice.

That MAP sensor alarm is maybe something to check. I don't know whether your engine has Manifold Air Pressure (MAP) and Throttle Position sensor (TPS), or also a Mass-Airflow sensor (MAS), but I suspect an outboard can be designed just fine with only a MAP and maybe a TPS.

Assuming only MAP or MAP/TPS, but this is probably true with MAS also: With the engine off but the ignition on, the MAP isn't doing anything. When you engage the starter, one of a few things is done. 1. Either the engine starts using the MAP to meter fuel based on manifold vacuum, or 2. the engine goes into a start mode where fuel is automatically metered. I suspect #2.

With one plug out, your engine produces much less vacuum, possibly enough to trick a bad MAS to deliver enough fuel to allow the engine to run. A bad MAS might not signal enough to deliver any fuel at idle, though. It sure looks like your engine is fuel starved. What happens if you spray a bit of gasoline into the intake right as it starts?

Initially, I thought that possibly your cam might have jumped a tooth on the belt. It might be worthwhile to check your compression first and ignition timing second either way.

-- DW

 

[webbd]

Just one other thought...

After I responded to your post, I thought back to the second video and realized it was missing something important. When cranking the engine, there was no water being delivered to the water pump.

Your water pump is a rubber impeller inside an aluminum housing. With lubricating water, it's a pretty sturdy arrangement. Without water to lubricate it, it's extremely fragile. The rubber will rub off in chunks like a muscle car doing a burnout. Larger chunks can get caught in the engine's water passages and cause overheating. You don't want to rotate the engine without water, even for seconds, not on your driveway, not at the boat ramp before offloading into the water, really not ever.

On many of these engines, the water pump housing is a thin stamping of aluminum that can also be shredded by an impeller turning without lubricating water.

If your impeller can be removed without dropping the lower leg, and if you had alreay done this, then please disregard my comments, but then I'd advise that an aluminum engine will heat up very quickly without cooling water, so please be careful. Otherwise I'd recommend checking your impeller before you put it back on the water, and if your first video at night was also without water, I'd recommend checking it before you even put the engine on a hose.

-- DW

 

[racerone]

On many of these SUZUKI engines the water pump housing is solid / hefty stainless housing.----????----And I would say you have to remove the lower unit to service the impeller on most big outboard motors !!

 

[ct1762@gmail.com]

i wasn't ever aware of an impeller that got hot enough to shred aluminum! wouldn't the neoprene rubber just melt?

 

[boobie]

Is it possible there is something wrong with the starter motor where it can't spin the motor over fast enough with all the plugs in but get rpm with one plug out ????