1990 75hp Mercury

[Big Fish Hunter247]

I have 1990 75 hp Mercury my question is I can prime it when I first start to go but when the motor is tilted up for any length of time it loses it prime is there anything that can be done or does that mean the carbs have to be rebuilt? Another question is when its cold out like 50 and below the motor has a "hiccup" is there anything that can be done about that?

Big Fish Hunter247

[BoxMN]

That is just normal, nothing wrong with your carbs, just gravity letting fuel flow back to tank... Either leave the motor tilted down, or hit your choke (I always called it choke, though I guess it might be prime button, pushing the key in) or give your bulb a squeeze, and you are all set.

[Capt. H (Ret.)]

I had this motor in a 90 horse and it was best to start it when trimmed all the way down. Never rebuilt the carbs but I think it was cold blooded. The dealer told me to pull the gas and let the carbs run dry when leaving the lake. I don't remember any problems when trimming the motor up during operation. Sometimes I swore at it and it started!!!

Mike

[Raider4ever]

I have a '98 25HP 4 Stroke Bigfoot that doesn't start well after storing it trimmed up. But, put it back down; prime the bulb until hard; give it a few pulls and it goes. Mine is also pretty cold blooded, she takes quite a few pulls to get her going in early May and October.

[Savage Brewer]

I had a late 80's merc that drained when tilted up, that is normal because of how the carb bowl floats operate.

If you have an inline check valve in place it will prevent fuel from draining back into the tank. I think some primer bulbs have this built in.

In cold weather both of my older motors could be a little tempermental until they got good n warmed up.

My newer motors with EFI dont have that issue.

Depending on the hicup as you put it, a good tune up might make it better, but realistically dont expect a 25 year old carbureted 2 stroke to run as well as a modern DFI or EFI engine.

Another thing I did to help in cold weather was switch to AmsOil synthetic 2 stroke oil, just seemed to run a little better in cold weather.

Also I remember always putting in new plugs 2 times a year. Once in the spring after the first hour or two of running out of storage, and then once again in the fall before things turn cold. I believe in the fall/winter I ran with the plugs gapped just a small bit tighter.

Another thing is check your thermostat and see if it is letting the engine warm up.

Do you know when the last time the carbs have been cleaned and sync'd? If it has been 6 years or more, maybe having a shop pull the carbs, put them through good cleaning, tune, sync and new plugs might pull it around and get rid of that.