Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

[glenlyn]

The boat I have just purchased has a Mercury 40hp 2 stroke thuderbolt ignition outboard.
I would be interested to know what year and model it is.

I am also having an issue with the forward speed it is producing.

The engine sounds good but I cannot achieve the revs.

I am checking the compression today but would like to know what it should be reading.

If the check proves ok then I have been told that it may be the carb as it has been stood for some time.

The engine has some blue smoke coming from it. Is this running to rich?

The engine cuts out when you close the choke. Not sure what this tells me?

If anyone else could offer advise it would be appreciated.


many thanks

Jon

 

[turbinedoctor]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

The boat I have just purchased has a Mercury 40hp 2 stroke thuderbolt ignition outboard.
I would be interested to know what year and model it is.

I am also having an issue with the forward speed it is producing.

The engine sounds good but I cannot achieve the revs.

I am checking the compression today but would like to know what it should be reading.

If the check proves ok then I have been told that it may be the carb as it has been stood for some time.

The engine has some blue smoke coming from it. Is this running to rich?

The engine cuts out when you close the choke. Not sure what this tells me?

If anyone else could offer advise it would be appreciated.


many thanks

Jon

A little blue smoke is good, two strokes smoke due to the oil you mix with the gas.

It cuts out when you close the choke. To much choke will shut it off, flood it out.

Carb kits would not hurt along with a good cleaning.

Not sure about the compression.

What is the model number, how many cylinders? Any other information you can gather will help narrow down your model and year.

 

[glenlyn]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

many thanks for helping me out. yes when you attempt to close the choke (if i am correct the flap starts to close when you attempt this) then the engine cuts out?

where would i find the serial number

I have attached a photgraph of the engine if it helps in any way

thanks again

 

[turbinedoctor]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

I beleive some where on the mount that attaches to the transom, maybe on the center pivot colum.

 

[glenlyn]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

hi

there is no serial plate but there is a serial number .the serial number is difficult to see but it reads 918521 and i think the last number is 9??

 

[turbinedoctor]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

Here is a link to some parts break down drawings, just select your HP and Serial #.

http://www.mercruiserparts.com/selectModels3.asp?type_id=MAR

 

[glenlyn]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

would anyone know where i can get spare parts. i need the clamp bracket assembly but prop need to get a salvaged unit??

 

[leobellanaty]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

Hi, I have a 92 Mercury outboard 60 HP that does the same thing. It starts ok, then after it passes 2400 Rpms usulaay in 10-20 seconds in shuts off. today I had to go back to the pier really slow so it wouldnt do it anymore. The carbs have been cleaned 2 months ago and the plugs are new. Help Please. Thanks

 

[muncher9707]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

I realize this is unrelated to this post but am new here and not familiar with exactly how this all works.

I have a 1977 Model 402 40 HP 2 stroke 2 cylinder engine, serial 5042224 on the 1977 Cobia 14 foot runabout boat I just purchased. I dropped the motor and put water to it via a motor flusher and ran the engine. It runs great but now it is stuck in the down position and cannot be towed that way. There is a tab on the left hand side of the engine that looks like it needs to be pushed (or pulled) to enable the engine to be put back into the traveling position but for the life of me I cannot figure out how it works or something is wrong. I had a friend look at it and he cannot figure it out either. I know this seems like a silly problem but I cannot tow the boat to have it looked at with the engine in this position and any help with this would be greatly appreciated. Hope someone reads this and can help.

 

[Milduff]

Re: Mercury 40 hp 2 stroke outboard thunderbolt engine problems (can anyone help)

Put gear selector in forward this releases the lock down then lift engine and lock in up position.......