Mercury Blackmax trouble starting

[boudreux]

I have an 88 mercury blackmax xr2 150. Sometimes when i put in the water, the motor will just turn and turn and turn and not fire. Once i do finally get it cranked it shoots out a lot of smoke like its flooded. I have replaced the spark plugs as well as the fuel filter. Even after i fish a while after running the boat it will still struggle to crank, other times it will crank right up. But when i put the ears on it at the house it cranks right up on the first time? once i get it running it runs great. Any ideas?

 

[Fuzzytbay]

Re: Mercury Blackmax trouble starting

Carburation? Have they been cleaned lately.
Enrichener/choke problems.
Wiring?

 

[Toxarch]

Re: Mercury Blackmax trouble starting

Mine has similar problems. I have found that I can tilt the engine up to where the water intake is the only part of the lower unit in the water and the engine starts right up, then I drop the engine down into the water.

 

[sschefer]

Re: Mercury Blackmax trouble starting

You both are describing the effects of back pressure on the engine when it's in the water vs. no back pressure when it's on the muffs. Typically this is an indication of low compression but can be mimicked by things like dirty carbs, bad trigger, etc. Do a compression test and let us know what the results are.

 

[boudreux]

Re: Mercury Blackmax trouble starting

I will check out the carbs this afternoon. I don't think its a problem with the choke as i am getting plenty of fuel for startup. I'm not sure about a compression problem either because it runs like a scolded dog when i finally get her cranked.

 

[sschefer]

Re: Mercury Blackmax trouble starting

I will check out the carbs this afternoon. I don't think its a problem with the choke as i am getting plenty of fuel for startup. I'm not sure about a compression problem either because it runs like a scolded dog when i finally get her cranked.

Try advancing your initial timing a little. Not too much 1-2 degrees at most. Your idle should increase also. As long as it doesn't go over 800 rpms and it starts easier then it's something you can probably live with.

 

[j_martin]

Re: Mercury Blackmax trouble starting

Mine was getting iffy on starting, then it became obvious the starter was going bad.

If it doesn't crank briskly, it'll balk at starting. If it grunts or struggles at all when you crank it, either the battery or the starter or both are in need of service.

hope it helps
John