mercruiser 188 fuel help

[slim6969]

Hey everyone I picked up a boat last year a 1975? 20fter. This boat has the mercruiser 188 in it.

I had it out a few times just short runs

But when I took it out for a long run it died on me ( under power and running 50mph the engine just stoped) and would not restart.

I originally thought it was the coil as it was super hot to the touch but….. I think the engine may have been overheating. Temp gauge didn’t show this but 1 After the engine shut off it became really hard to turn over. 2 I had my wife pumping the gas to see if the gas was leaving the carb and going into the intake manifold it was but the gas that hit the bottom of the intake manifold would boil off I could see it and hear it !!!

It seems this engine draws a lot of amps to turn it over it will kill my battery’s fast they are brand new and designed for boats Not sure if this is a starter issue or something with the engine itself.

I’m wondering if a cracked block or blown head gasket would cause this gas boiling issue?

Where / what should I do first ??

 

[04fxdwgi25]

Sounds like it overheated.

 

[Scott Danforth]

Hey everyone I picked up a boat last year a 1975? 20fter. This boat has the mercruiser 188 in it.

Where / what should I do first ??

the first thing you should have done is all the maintenance that the prior owner did not do

first thing was pull the drive and split it. replace the raw water pump

then inspect the gimbal bearing, u-joints, bellows and alignment

most likely you also need new bellows.

regarding your overheat. hope to hell you didnt. because if you did, you now get to pull the head and replace the head gasket because the 470 is known to eat head gaskets with the slightest overheat.

 

[kenny nunez]

It is possible that that the drive locked up for lack of gear oil. As SD said you should have had the drive and engine checked out before you used it.

 

[nola mike]

.

regarding your overheat. hope to hell you didnt. because if you did, you now get to pull the head and replace the head gasket because the 470 is known to eat head gaskets with the slightest overheat.

I think we're talking about a Ford V8?

Op has some trouble shooting to do. As far as turning over slow, you want to clean up your wiring between the starter and battery and the grounds, if that happened before the overheat. Is the engine turning over? Do you have spark? You can get an overheat from a blown hg, but more likely the other way around.

 

[racerone]

You did put a new impeller in the water pump I hope.----First thing that needs to be done on a ---" new to you outfit "-----Stern drive or outboard motors should get a new impeller about every 5 years at the least.

 

[slim6969]

So just to update

Yes I did change the impeller in the outdrive did plugs wires cap rotor points as well Cleaned and rebuilt the carb


The boat ran well for about 45min wot we stopped did some swimming was there for 3+ hours

On the way back in after about 5min of running wot it just quit Fell flat on its face.

Was able to get it started. Did this repeatedly until it would not fire anymore. Killed my batteries and had to be towed back in.

Where we got dropped off from the tow in was about half hour away from the slip. I went back the next day changes the fuel water separator checked for water in the gas. Swapped out the coil for a known good one made sure I had spark and decided to drive it back to the slip

Got 2min out and it fell flat on its face again and would not restart. I stayed close to shore took me 5 hours to walk the boat from where it stalled to my slip only because I had to go around a point was not a straight shot back

Went home charged up my batteries The next day went and it started no problem and I let it idle for well over an hour before I shut it down and pulled it out for the rest of the summer

 

[dubs283]

You need to determine if you are losing spark or fuel related to the engine shutting down. Based on your findings there are many avenues to consider when troubleshooting the root cause.

WAG based on original post is the charging system is failing resulting in dead batteries. This could be only one of a few issues you're dealing with