1989 omc seadrive 140 hp advice needed

[Cdnpokerface]

First time poster... I've done a lot of reading on this over the past few days and can't seem to get the answers in looking for so here's my situation...

1989 sportcraft 270 with twin omc 140 seadrives

Stbrd engine starts and runs great
Port has following symptoms
- hard to start usually have to use fast idle
Runs rough at idle bucks a lot and will some times stall at idle in neutral
- tach is intermittent not working
-no oil alarm sometimes sounds in neutral
- gas bulb seems to go a little soft after sitting

Here's what I have done

New plugs champion ql77jc4
Compression tested 120-123 across all four cyl
Run deadpan and premium fuel thru it

I have tested the non working tach on the stbrd engine and it works fine I also removed the grey tach wire and placed on yellow/grey and tach works fine also with port engine running I sometimes have no charging at battery.

When I get oil alarm I pump oil buld 2 or 3 times and it will go away

New gas/water seperator filters in spring

I bought a new voltage regulator because I'm fairly confident this is my issue with tach and charging

My questions are as follows

Would a bad regulator cause it to be hard to start and rough idle?

What else should I look for ?

Will a bad regulator effect the oil alarm? I've read it can due to the fact the vro alarm uses tach signal information to decide if engine is pulsing enough oil based on engine speed


Any help or advice is greatly appreciated

 

[Cdnpokerface]

I should add I haven't replaced the regulator yet as it just arrived

 

[racerone]

The regulator is part of the battery charging system.----The ignition system is seperate from that.---A weak battery / bad starter / bad wiring can lead to " slow cranking " and that translates to marginal spark / no spark and a hard to start condition.

 

[Cdnpokerface]

Thank you for the reply...

The starter does sound a little slower than the starboard side but I can get the engine running with fast idle advance but it seems to buck and stutter near idle and will sometimes die ...

 

[racerone]

Test spark with an adjustable air gap tester.-----The only acceptable spark test for those ignition systems is a 7/16" gap.----It must jump that with ease.----Tester is easily made with 2 pieces of wire taped to say a stick.-----A gap of 7/16" between the wires and stick one end in the blug boot and the other end to engine block with an alligator clip.----

 

[Cdnpokerface]

Thanks again. I will try that tomorrow when I replace regulator, if spark happens to be weak where should I look? Stator, cdi, coils?

 

[Cdnpokerface]

UPDATE

I replaced voltage regulator which fixed my tach issue ... I was still having a hard start rough idle condition so I checked spark .. Good blue spark on all 4 cyl, I replaced plugs and gapped to .035. I also took my fuel pump from Starboard side and put it on my port side to eliminate fuel pump.

Engine starts and idles... Take boat out for a spin ... Get no oil alarm while idling out of harbour on port side engine still with the known working vro pump from stbrd side and now that my tach is working the port side won't make more than 3000 rpm and seems to idle a lil rougher again so not sure if I've fouled a plug...

What should I be looking at now?

 

[Cdnpokerface]

Also checked flow from fuel tank on port side doesn't seem to be any blockages.

 

[racerone]

You need 4 things for engine to run--------Spark , at the right time.----Fuel.--------Compression -----And the 4rth is crankcase compression.----------So use a timing light and verify you have spark on all 4 at full throttle.-----Perhaps mark your flywheel with TDC for each cylinder and verify that you get spark at the right time for each cylinder.-------Look into the carburetor bores at full throttle and compare fuel coming up the main jets.---Use a strong flashlight to observe this.---Crankcase compression is a little harder to trouble shoot.

 

[Bosunsmate]

You sure its not overheating alarm?
Do a drop test on each cylinder

 

[Greg O.]

What is the condition of the destributer cap and rotor? As well as plug wires. Almost sounds like the spark may be jumping places it shouldnt. You could have moisture inside the cap or corrosion, or a bad rotor. Bad plug wires could be allowing the spark to take a path to ground. Just a thought. Let us know what you find. We all learn that way.

 

[boobie]

Distributor cap and rotor ??????????????