79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

[old bird]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

I'd like to see pictures of his.
I also have one.

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Alright..

Boat is up and running here is the problem.

It start to overheat very quickly when it is in the water and we try and go over 2000 rpms. The temp gauge start to shoot up to 180 - 200 then 220... if you back off the boat starts to cool down and come back to 150 on the temp gauge.

Also the Gimbal bearing is making a racket at the 2100-2500 rpm mark....

I think somewhere in the outboard is the problem. I know the water impeller was replaced last year...

Would it be cheaper to just buy another outboard or the lower section of the outboard?

Thanks for the help guys. (pics to follow)

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

outboard serial # 5354111

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Bond-o thoughts?

 

[IVAZ]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Alright..

Boat is up and running here is the problem.

It start to overheat very quickly when it is in the water and we try and go over 2000 rpms. The temp gauge start to shoot up to 180 - 200 then 220... if you back off the boat starts to cool down and come back to 150 on the temp gauge.

Also the Gimbal bearing is making a racket at the 2100-2500 rpm mark....

I think somewhere in the outboard is the problem. I know the water impeller was replaced last year...

Would it be cheaper to just buy another outboard or the lower section of the outboard?

Thanks for the help guys. (pics to follow)

Are you asking if it would be cheaper to buy a new drive vs fixing your overheating problem?
Did you get new manifolds?
Even with a new drive you would still have to address the gimbal bearing.

 

[MikDee]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Save your money on the ignition and carb, rebuild what you already have. You will not gain major improvements "upgrading" them. Put the money you saved towards new manifolds, so you don't destroy the engine.

Ditto!

 

[MikDee]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Alright..

Also the Gimbal bearing is making a racket at the 2100-2500 rpm mark....

I think somewhere in the outboard is the problem. I know the water impeller was replaced last year...

Would it be cheaper to just buy another outboard or the lower section of the outboard?

Thanks for the help guys. (pics to follow)

NO, keep your drive if it's working good, but the Gimbal bearing is in the transom plate, not the drive itself, if you're sure it's that, you must remove the drive leg to fix it.

As far as overheating, check the obvious first, make sure the main water feed hose going into the boat, located on the outdrive plate in the back, under the bell housing, is not kinked at the bend, they have a tendency to do this with age, it is a special Mercruiser only hose. Next check this same feed water hose inside the boat, where it comes in, goes through the power steering cooler, then goes to the main water pump on the motor. You can run it on the garden hose, and remove this hose from the engine water pump, to check for flow (tempoarily).

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

IT is an 888 outdrive. (Not an Alpha Gen 1)
The hose theory makes sense...
Does anyone have a parts break out chart for this hose?

It only over heats when we have the outdrive is trimmed down and we go over 2000rpm. The temp comes right back down.

We we first put the boat in the water and ran it.. It dint overheat. But after about 5 minutes of cruising it instantly overheated. (10 seconds..)

Local mechanic familiar with the boat thinks it is a Exhaust restriction that is
causing it to overheat.... He was suggesting running transom exhaust to alleviate the possible exhaust restriction but I am not wanting to deal with all the exhaust noise.

So in Recap here are my 2 possible problems/solutions.....

1. Water hose in outdrive being kinked...
2. Exhaust not exiting fast enough at rpm's above 2000...

 

[180shabah]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Exhaust restrictions kill power, not increase heat. However, old manifolds and risers can have obstructed water passages. They allow enough flow to cool the engine at idle, but as you add throttle (and heat) you don't have enough flow to keep up.

 

[MikDee]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

Maybe the flappers in the Y-pipe (main exhaust going out of the boat) are damaged, causing it to overheat?

Anyway, is that a Ford, or Chevy engine? You say it's an 888 drive, that usually means a Ford 302-2bbl = 188hp, hence the term a "Merc 888", not necessarily describing the drive as an "888", but usually if it's an older drive, it's a Type 1 drive, (pre Alpha) used on most all early Mercruisers.

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

pics..

 

[IVAZ]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

I?m no drive expert but it looks like my old pre-alpha. The engine is definitely a chevy.

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

What type drive is mine? Pre-alpha? (Mechanic said 888 but that sounds wrong..)

I need to order the raw water pump.. Impeller kit and the Gimbal bearing..

 

[MikDee]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

What type drive is mine? Pre-alpha? (Mechanic said 888 but that sounds wrong..)

I need to order the raw water pump.. Impeller kit and the Gimbal bearing..

As I said, It's a Mercruiser "TYPE 1" drive!

By the way, That boat sure is Purdy!!! and looks in Great shape for it's age!

 

[illtww]

Re: 79' Formula Thunderbird Merc 350 Engine Carb/ Iginition Q's

thanks!

I plan on painting it. Metallic grey or Black.. (Black out the whole boat)

IT is an 898 Mercrusier type 898..

No i need to find the impeller kit and the raw water pump.

Des it matter that it is missing the exhaust bellows? Exhaust is just coming out of the upper part of the outdrive...