Looking for help on Mercury 800 80hp

[firefighter7128]

Im new here guys and surly not savy on boat motors. Tonight i had a old Arrow Glass with a Merc 800. This was bought in an auction and was delivered this evening. Boat is near mint. just needs a good polish.
The motor is unclear as it is dark outside and will have to takle in the a.m.

The previouse owner states that they ran the boat several times thru the summer. One day after 3 hours the motor stalled. After a few tries they got it back up and headed in. They set out again the next weekend and the boat died after about an hour and they were finaly able to get started and head home. guy says he cleaned the carb (i assume spray it) and checked the lines then took it back out. he said he got 100 yard from the dock and it died and had to swim the boat back. hasnt started since. So to me, if this were a car i would go with a fuel pump, but since its a boat i will ask someone elses opinion. also, any suggestions on who or what pump to get?

 

[Laddies]

Re: Looking for help on Mercury 800 80hp

You can overcome a bad pump by just using the primer bulb, but it does sound fuel related. If the w/pump is working I would start by cleaning the carbs and the fuel pump kit, while cleaning the system be sure to refill the tank with fresh fuel mix and flush out the lines or you stand a chance of pumping it back full of crude.

 

[firefighter7128]

Re: Looking for help on Mercury 800 80hp

Thanks for that info. I must confess, I know NOTHING about boat motors. I just charged the batt. It is turning over so im moving on. Fuel is new, now im trying to locate the carb. seriously. lol. Is there a download anyplace on this engine?

 

[Laddies]

Re: Looking for help on Mercury 800 80hp

You need to get a manual, there are no downloads for service manuals and if you want to do your own repair you will need one. The OEM manuals are the best but any manual is better than none.

 

[firefighter7128]

Re: Looking for help on Mercury 800 80hp

roger that. im already shopping for one. I just was tinkering on the engine. Fuel pump is working just fine. im afraid its the carb. I assume they make kits?

 

[James R]

Re: Looking for help on Mercury 800 80hp

Laddies is telling you true. It would help if we knew what year motor you have. Look on the transom mount under the front of the motor for an ident plate and get the numbers. If the numbers are not there look for a plate on the side on the mount.

 

[firefighter7128]

Re: Looking for help on Mercury 800 80hp

I found that the fuel pump is working by disconecting the hose and hitting the key for a few seconds. That leaves me to think that the carb or carbs is bad. Engine serial number is: 2989609. I found the carbs. looks a bit tough to get out but i also learned that there are kits. how tough is this to do?

 

[Chris1956]

Re: Looking for help on Mercury 800 80hp

That motor is very compact. To remove the carbs (I presume that are sidebowl carbs), you need to remove the front, top and wrap cowling, and the top and rear cowling supports. Next remove the starter, after first disconnecting the electrical at the plug on the side of the motor.

Merc and Sierra make gasket sets. Check the floats in the carbs. They are soemtimes made of foam and deterioate, or hard plastic and develop cracks. Replace them if you see any of these issues. You can also replace the inlet needles and seats, if they look suspicious. The originals were brass seats with rubber centers and SS needles. Sometimes the rubber hardened or cracked.

 

[firefighter7128]

Re: Looking for help on Mercury 800 80hp

Before i move on with the carbs, i want to confirm im getting spark, so here is a stupid question.... What is the best way to check for spark? Batt is charged, Engine turns when i hit the key and plugs are new but after looking at the cap, i started thinking more about confirming spark.