Confused and frustrated

[flydragonfly]

I have a 1991 3.0 mercruiser I think bought it and was started at the guys house seemed to run fine.didn’t run very long got it home took to the lake and problems starting wouldn’t stay running if it did start.rebuilt the carb would start but couldn’t throttle up would die so I then had problems starting again took throttle cable off of carb to manually accelerate the motor to see if it was I shift kill switch issue keeping it from running and started would idle rough couldn’t throttle up now won’t start.so I have a few questions
On the 3.0 mercruiser is the cooling system something that is closed system requires coolent and if so how and where do I put water and. Coolent?
Not finding a resivore for overflow etc I was thinking it that water is pumped from lake into motor and back out to lake but seems a bit far fetched so how does the cooling system work?
I

 

[alldodge]

My guess is yours is open cool, so you would have raw water drawn in by the pump in the out drive leg.

If it won't start so need to find out if its lack of fuel or spark that is missing

Look on the motor for a serial number?
It will be a number (0 o 1), a letter and 6 more numbers EXP 0W123456

 

[Rick Stephens]

In this case a motor is a motor is a motor. Either it is getting fuel and no spark or it is getting spark but no fuel.

Also, with a new to you boat you should get a compression test and see what your baseline motor condition is.

 

[racerone]

Agreed ----Compression test first.-----Install a new raw water pump impeller.-----Lots of first time boat owners these days !

 

[achris]

... I was thinking it that water is pumped from lake into motor and back out to lake but seems a bit far fetched...

Nope, that's how 99% of pleasure craft inboard engines are cooled. (and 100% of outboards. )

Chris......

 

[poconojoe]

Since you are not familiar with how your engine is cooled...
Make sure you don't run the engine with the outdrive out of the water unless you have a garden hose connected. Not even for a few seconds.
A lot of damage can occur when these engines overheat.
And don't ever run the engine with the outdrive up all the way (in trailer position). That's bad for the u-joints.

 

[Grub54891]

Sounds like you have never had a boat of this caliber. I think you need to keep asking questions here, and talk to a known professional in your area and get some knowledge on how this all works. Anyone can turn the key, but what happens in the bilge/motor/under the hood area they have no idea.

 

[flydragonfly]

So I bought a mercarb rebuild kit, the carb was in very rough shape with a lot of oxidation and I attempted to rebuilt it some I couldn’t get a few things apart etc.it didn’t go well so I’ve been looking for another carb but they all are 295.00and up is there anywhere I can find used parts or a different route I can go.
Maybe there’s somebody that can refer me to a local person near at cloud man.also I got the boat to start by taking the cable off and manually accelerating the engine it was hard to keep running had to feather it to keep from dying thought I hear a lifter noise once .driving me crazy.

 

[Grub54891]

IF you didn't break stuff on the carb, Possibly it can be saved. Take it to a known shop or person who is good with carbs, and have them rebuild it. If I knew where you were, and were close to my area I could do it for ya.

 

[poconojoe]

If there's no one near him, are there any places online where they can either rebuild his or maybe sell him a rebuilt and he can save some money by turning in his core?
Just a thought...