HELP - 150 Mercury (update)

[stmichael]

A friend of mine has been having troubles with his 1978 150 h.p. Mercury OB. Here are some of the troubles he is having.

1. motor does not idle well at all even when warm.

2. motor will be running higher than idle, try to trim up and motor will die. Trim it back down to get it to run...really bites at the landing.

3. This has had a tune up/so called powerclean

4. Bogs down coming out of the hole

5. runs beautifully on plane

The boat/motor has been to a dealer, somewhere in Chisago not real sure of the name, I should probably leave that out anyway... they did the tune up and so called powerclean, they say the motor is in excellent running condition, he brought it to the lake and same problem prior to bringing it in. He did not want to bring it back to that particular dealer just to give it another "powerclean" It has been sitting since ice off last year..

We were thinking maybe the carbs need to be synchronized? my question is why would the motor run well for the dealer and he gets it back after many months of waiting and performance is still in the toilet?

Any suggestions as to what the problem(s) could be?

Or know of any good mechanic that could take a look at it?

Not looking for freebies, just want to help him get it running again....another fishing trip coming up Memorial weekend.

Thanks in advance.

[gunflint]

The first question that pops into my mind is how much time and money does he want to put into a 30 year old motor? Sometimes you're just better off upgrading and spending more time on the water than working on or waiting on an older motor. Just my 2 cents.

[Valv]

The Tower of Power, that's how they were called the old 6 inline.

I would bet a good carb rebuild will do the job. The "powerclean" thing doesn't sound promising to me, I bet it's just SeaFoam in the gas.

Find another mechanic and have carbs rebuilt.

[stmichael]

Gunflint I do not know if he has the money to buy another motor of this size. I am sure if he did, there would not be a question of getting it fixed.

Valv, thanks for the input I am going to do some finger walking...anybody have any experiences in the north metro with a mechanic?

[Valv]

Quote:

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......It has been sitting since ice off last year..

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I didn't pay attention to this, but I hope they winterized it.

Otherwise it will definitely need a carb rebuld kit on each of the 3 carburetors, also rebuild the fuel pumps.

Sitting with old gas the whole time wil have gummed up everything.

[stmichael]

I hope he did too! This guy is pretty anal about his stuff. I'd hate to see him slacking in this area.

According to him it has two carbs, and is a V6

[kjgmh]

Might want to check if the crankcase halfs are leaking. Spray some brake cleaner along both sides of were the crankcase halfs join. If hear a change in running it is leaking. Pretty common on the old inline 6.

[stmichael]

If the halfs are leaking any idea if it is repairable? if so what would be the estimated cost...ballpark? arm, leg, couple of kids...

I MUST REPEAT: THIS IS NOT AN IN LINE 6,

IT IS A V6

[stmichael]

Update on Merc:

The motor was finally brought in for repair, so far, the stator is the problem.