Logo
FULL SITE MENU

88 Nova II Port engine dies after running about 30-40 min

E

Egough1

New member
Let me start by saying this is my first I/O.

i bought the boat and instantly had to rebuild both stern drives due to water in them and I wanted no problems when I took it out.

Now that I’ve had it on the water the port engine will die out. Cruising around 3000 rpm the engine will spit and sputter then die completely.

Put it back on trailer. The following morning I replaced the fuel water separators and all 16 plugs. Still has the same issue. Have since replaced the separator again on that engine and the ignition coil. Still have the same problem.
 
What type of fuel pump does the "dying" engine have? What ignition system does it have?
You have a ready supply of parts w/two identical engines. You can swap parts one-by-one to find the failing part.
 
Mechanical fuel pump on both engines. It has a distributor but not a style like I’ve seen. This one has a spider gear and what looks to be a photo sensor for timing. It has a thunderbolt IV ignition box.
 
When it dies, you need to immediately determine if it has spark or not. If not, an overheating electronic component might be the reason.

Swapping parts may take too long (the problem could disappear) and trick you.

Jeff
 
I didn’t have my plug tester with me last time I was out. I will definitely take it with my next time. I guess I need to throw a large tool bag in the boat with me. Need to get it figured out before I have to winterize!
 
My instinct would tell me to investigate the fuel supply. It starts and runs fine, so it's probably not ignition. It might just be running out of gas. Mud wasp clogging the tank vent? That can do it.
When you change fuel filters, dump the contents of the filter into something that you can see if there's gook in there.
 
I know when it dies i plugged in a spark tester. It has spark. I just replaced the fuel hose thinking that maybe it was collapsing inside. The port engine seems to run better than the starboard until it starts cutting out and dies. Im coming to wall on where to go. Im wondering if it would be the fuel pump not supplying enough fuel while under a load.
 
It's possible that your anti-siphon fitting is clogging with crud in the tank as you run the engine at cruising speed. This is the fitting that's right on top of the fuel tank, your fuel line probably connects directly to it.
Also, to isolate the problem, you can temporarily use an external fuel tank (such as one for an outboard motor) to see if the problem is prior to the fuel reaching the fuel pump.
 
could also be crud in the tank accumulating on the inlet screen of the fuel pick up tube...a vacuum gauge in the fuel line at the fuel pump will help verify a fuel supply issue,....
 
Both engines connect to the tank 4” apart toward the back of the tank. When I had the fuel line off I connected the tank side first. I blew lightly on the line and could hear it bubble in the tank. What Mills me is that only the one is affected. Would the carb cause this issue? Maybe a float or inlet inside the carb? I changed the screen in the front of the carb.
 
if its crud inside the tank, it will only collect on the screen (at the bottom of the tube) with the engine running....you shut off the engine, the 'vacuum' disappates and the crud falls off. the problem side could have a longer (deeper) tube into the tank and is the first one to collect the crud.

you could swap the hoses for testing, if they are long enough...but you stil won't know for sure until you connect a gauge...
 
Back
Top