2.5L hesitation after 30ish mins then runs fine

[Adam_c]

Need some advice on my 1990 2.5l / 3.0 mercruiser V171 invader Started no problem, drove about 20 mins the had hesitation for about 4 seconds then ran normal.

Drove another 30 mins a bit more hesitations but didn't stall. Drove for about and hour and a half one way. Got back in started right but again about 30 to - 40 mins back hesitates for about 5 seconds and resumes driving normal

Then almost back stalls can't get it Started... Battery dies... Get back to boat launch from being towed started right up!

Does this sound like water in the lines that onces passes through runs fine or debris blocking the gas somewhere? I've heard others mention the distributor.

Happened last year but never left me stranded. Also the big rubber water tube on the left is empty shouldn't it have water in it? I'd like some help before I go replacing unnecessary parts please.

Also before this trip I went to replace the fuel filter and it was almost flat inside (paper one) could debris from this clogged anything?

I've had people say could be a over heating issue although temp gauge read about 100 the whole time.

​​​​​​​Thanks in advance

 

[Bondo]

Also the big rubber water tube on the left is empty shouldn't it have water in it?

Ayuh,...... Welcome Aboard,...... Which hose is this supposed to be,..??..??

Temp gauges read water temp, but won't read hot air,......

 

[Adam_c]

[No message]

 

[Alumarine]

That hose attaches to the engine water pump and will be empty when the motor is not running.
With the motor running it should be hot.
100 F is way to low. It should run at 140. Has the thermostat been removed?

 

[Adam_c]

Not yet, changing that is my next plan off attack.

 

[Bondo]

That hose attaches to the engine water pump and will be empty when the motor is not running.

Nope,.... Sorry, this is Untrue,...... Once the motor is run once, that big u-shaped hose is Full of water, til the block is drained,......

I'm guessin' the temp gauge don't work, because the motor is bone dry,......

 

[Alumarine]

Nope,.... Sorry, this is Untrue,...... Once the motor is run once, that big u-shaped hose is Full of water, til the block is drained,......

I'm guessin' the temp gauge don't work, because the motor is bone dry,......

Good to know, I stand corrected!
I guess it feels empty because there's no pressure?

 

[Adam_c]

I've replaced the impeller so hopefully I did t screw that up and it is just the thermostat because it sat all winter.

 

[Adam_c]

No thermostat this is where it's suppose to be right?

 

[Alumarine]

Yes, you need one there.

 

[Adam_c]

Am I missing the housing or it just drops in there?

 

[Scott Danforth]

first.... its never the coil or distributor
second.... for your fuel filter to be flattened, you have a serious issue with crud in your fuel system. start at the tank and clean everything all the way to the intake manifold.
third, yes, you should have a thermostat
4th, what do you have, a 2.5 liter or a 3.0 liter? being a 1990, it should be a 3.0 as the 2.5 went away prior to that.

 

[Adam_c]

The boat is a 1990 but it has a 1989 2.5L
So got a new fuel filter, replaced it, cleaned up the thermostat housing and dropped in a new thermostat... Finally the temp gage was reading about 160 noticed when the boat warmed up it ran crappy looked a little further noticed I was low on oil

I must not have added enough when I did the oil change previously. Added just under a liter and started back up and runs smooth now.

Haven't had a chance to test it on water to see if the hesitation is gone but I hope what Iver done was enough. I guess will see and I'll update when I can get it back out.

 

[Adam_c]

Had boat back out, still stalls after it warms noticed oil drippings on top of the manifold also noticed oil coming out of the air intake filter when taken off and turned side ways oil drips out. So I would guess the stalling issue has to do with oil going in the carb? Why would oil be going from the manifold dripping in the carb but seems like an excessive amount probably causing the stalling issue.

 

[Adam_c]

Oil dripping from intake filter

 

[Adam_c]

Synthetic oil in Merc 2.5 bad idea?

Just realize I used synthetic, I've been having some issues with the boat hesitation after it warms up. Also notice oil coming from my air intake filter and all over the oil cover could using 10w-30 synthetic be the issue? If it spitting out the hose the attaches out the intake?

 

[Adam_c]

Scott Danforth any advice on my update?

 

[Scott Danforth]

do a compression check. you may have excessive blow by

 

[Adam_c]

Scott Danforth I do have excessive blow by, I over filled the oil accidentally and I'm using 10w-30 synthetic which I believe is thinner? I picked up some 15w-40 Rottella in hopes that proper level and thicker oil will help this possibly? Yes when I get the chance I'll do a compression test next. Also noticed heat tube was plugged so cleaned it out and adjusted the choke when cold cleaned the carb filter screen so I guess will see what happens once I get it started although my issues normally only happen on the water of course.

 

[Adam_c]

** UPDATE** FOUND WHAT COULD BE THE CULPRIT...

main harness plug if I wiggle any of the wires while it's in engine stalls, or apply pressure to the plug or wiggle it.