Port Engine Hard Start

[RelentlessWMD]

I have a Yamaha 242 Limited S.

The port engine is stubborn to crank over. It usually takes several tries and several seconds to catch and turnover. It also pulls the battery down very quickly, usually to the point that the other motor has to be on and the battery switch be in the parallel position. Often when it does turn over it backfires. This hard cranking happens 80% of the time and is less common when warm. once it cranks it runs rough (surging) for a few seconds. After that it runs great and no issues.
I have checked the timing and the spark plugs (good gap and not fouled), no issues. Batteries are healthy and the starter sounds strong.
I suspect maybe a bad ground, I have put an old set of jumper cables on the engine mounts and exhaust over to the other motor to see if that helped but didn't really notice a difference. From my studying the Ground wire is on the started under the exhaust and wanted a second opinion before I pull the exhaust off.

This issue started when i pulled it out last summer and only got to run it a couple times. Ran it last weekend and the issue remains.

Any thought and what else could be causing this and/or what to check?

 

[RelentlessWMD]

I ran the boat this weekend. Pretty well the same thing happening. I reached and wiggled around the starter wires and it seemed that the hard start was less common. If I wiggled them before starting it would start right up typically. Starter definitely sounded stronger Given this I believe I have a bad cable/connection.

I guess i will order a new exhaust gasket and plant to pull it off in the next week or so.

I believe the backfire and rough initial running experienced before must be from fuel build up from long cranks.

 

[FSH 210 Sport]

Do you have a service manual? If not get one.

Have you put in new plugs? Just checking old plugs will not suffice. Put in a new set to eliminate that possibility.

Have you checked the clean out plug hatch safety switches? See if they are loose, if not put a couple of quarters or something thats a 1/4” thick taped to the hatch to push the switches down farther.

Pull the safety lanyard out and put it back a few times to exercise that switch.

If any of those things don’t fix the issue then it sounds like it could be a pick up coil. Thats where the service manual comes in.. get a quality multimeter and check the ohm readings on the coil, while you are at it check the coil over packs on both engines and compare readings.

If you hare having to crank the starter so much that you have to use the emergency parallel switch then there is definitely an issue. What is the length of time you are cranking this engine? My initial thought is that if your battery is getting pulled down quickly the battery sounds like it is going bad.. how old is the battery and do you keep it on a charger? If so which one?

 

[Neutron]

I ran the boat this weekend. Pretty well the same thing happening. I reached and wiggled around the starter wires and it seemed that the hard start was less common. If I wiggled them before starting it would start right up typically. Starter definitely sounded stronger Given this I believe I have a bad cable/connection.

I guess i will order a new exhaust gasket and plant to pull it off in the next week or so.

I believe the backfire and rough initial running experienced before must be from fuel build up from long cranks.

If it cranking long before it fires why do you believe the starter is an issue?