50 hp thunderbolt help

[midgetme23]

I bout a 50 hp thunderbolt today and was wondering if they are good motors I got a 17 aluminum boat It is a 97 life guard boat I was wondering if it would be a good motor to out some money into to put on this boat I don't know what year it is but the serial # is 2740126 It is going to need a few parts. I know it is going to need the internal wiring harness but did some researching but afraid I might buy wrong one. It is going to need a complete rewiring job. It also I think is missing a few pieces. I really don't know what it is missing If you have any pics of the motor like mine I would like to see that way I know what I will need. Is there anyway I can check the compression before I rewire it so I know it is worth putting money into. Any thing else I need to check. Any info is greatly appreciated. I can post few oics of the motor if that would help.

 

[GA_Boater]

Re: 50 hp thunderbolt help

This the internal wiring harness. Mercury Marine 414-2770 Internal Engine Harnesses - CDI Electronics - iboats

Your motor is a 1967 Merc 500 going by the serial number.

 

[midgetme23]

Re: 50 hp thunderbolt help

thx gaboater any body got any more info

 

[carholme]

Re: 50 hp thunderbolt help

That s/n comes up as:

50 500 4-cyl 2736807 3008818 1970 USA

From here:

Mercury 2-takt, 4-cyl, 40 - 85 hp, produktions?r, modellguide

Parts List:

MERC 500-7/8 - Mercury, Mercruiser, Force, etc. Parts Lookup

The service manual you require is P/N: 90-68647

90-68647 in Books | eBay

In the interim, here is a link to the condensed version of the Clymer manual which will help you get started. Download it soonest to your computer as the link is short lived.

Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR-CYLINDER MODELS (1969-1989).


Gerry

 

[GA_Boater]

Re: 50 hp thunderbolt help

Oops, I goofed on the ID. Follow Gerry's links for info.

 

[carholme]

Re: 50 hp thunderbolt help

No sweat GA, not a big deal.

Gerry

 

[midgetme23]

Re: 50 hp thunderbolt help

thx for the help

 

[Urbina]

Re: 50 hp thunderbolt help

forget about that motor getting parts is going to be hard since they maybe obsolete.
look into a newer engine.
I'm not bashing old engines but getting parts is a pain i have a 1973 Evinrude

 

[GA_Boater]

Re: 50 hp thunderbolt help

forget about that motor getting parts is going to be hard since they maybe obsolete.
look into a newer engine.
I'm not bashing old engines but getting parts is a pain i have a 1973 Evinrude

Poor advice and simply not true.

 

[midgetme23]

Re: 50 hp thunderbolt help

I've got a 88 40hp Johnson tiller on boat now I was just want to put one with steering and controls in it. I bought a whole boat with the thunderbolt on it. Could I turn the Johnson into a steering wheel motor. If I could I prob would sell the thunderbolt to somebody for parts. The thunderbolt is in really good shape besides needing the wiring harness. Or would I be better of just fixing the thunderbolt

 

[kazek]

Re: 50 hp thunderbolt help

Checking compression on all cylinders.spark should be blue and jump 7/16 gap.wireing on those beasts is notorious to fail,can be replaced with little effort.lower unit oil should be checked for water intrusion and metal shavings.merc is goood engine

 

[Aaron Lariscy]

Re: 50 hp thunderbolt help

How about give us one example of a part you have needed but been unable to get for a 1973 Evinrude...

 

[bgc]

Re: 50 hp thunderbolt help

I've got a 88 40hp Johnson tiller on boat now I was just want to put one with steering and controls in it. I bought a whole boat with the thunderbolt on it. Could I turn the Johnson into a steering wheel motor. If I could I prob would sell the thunderbolt to somebody for parts. The thunderbolt is in really good shape besides needing the wiring harness. Or would I be better of just fixing the thunderbolt

Fix the Mercury, it'll run circles around the Johnson.

 

[bgc]

Re: 50 hp thunderbolt help

forget about that motor getting parts is going to be hard since they maybe obsolete.
look into a newer engine.
I'm not bashing old engines but getting parts is a pain i have a 1973 Evinrude

Check IBOATS for the parts for your Johnson or Outboard Motors, Boat Parts, Marine Engines, Inboard Boat Motor or Evinrude Parts - OMC - Mercruiser Parts - Boats - Crowley Marine
I personally rebuilt a 63 Mercury 500, new pistons, bearings, seals, gaskets, water pump, fuel pump, carbs, and new paint(Factory color). Even found new emblems and decals. Its all out there.

 

[midgetme23]

Re: 50 hp thunderbolt help

thx for all the replies

 

[midgetme23]

Re: 50 hp thunderbolt help

That s/n comes up as:

50 500 4-cyl 2736807 3008818 1970 USA

From here:

Mercury 2-takt, 4-cyl, 40 - 85 hp, produktions?r, modellguide

Parts List:

MERC 500-7/8 - Mercury, Mercruiser, Force, etc. Parts Lookup

The service manual you require is P/N: 90-68647

90-68647 in Books | eBay

In the interim, here is a link to the condensed version of the Clymer manual which will help you get started. Download it soonest to your computer as the link is short lived.

Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR-CYLINDER MODELS (1969-1989).


Gerry

I looked on the website for wiring harness but it don't look like it the right one I think it suppose to be 7 plug but guy said this is the one it calls for. Just want to no for sure before I order it.



This what my plug from controls look like

 

[carholme]

Re: 50 hp thunderbolt help

Well, what is it exactly that you are looking for? In your first post, you say you require an internal harness which is the one that fits on the engine. Yet, in your last post, you are talking about the long external harness, which runs from the remote control box to the engine where it mates with the internal harness.

If you need the external harness, you have to identify which type of control box you have. Is it one like this?

http://imageshack.us/a/img266/4852/46194058.png

Gerry

 

[midgetme23]

Re: 50 hp thunderbolt help

I am needing the internal wiring harness when I got the motor they had it pulled out. I posted the other pic showing my external wiring harness. It has 7 plugs. The internal wiring harness he showed pics of only has 6 plugs so I was thinking that would be the wrong harness I have looked at others on eBay and other website that have 7 pin plugs on the internal wiring harness

 

[midgetme23]

Re: 50 hp thunderbolt help

I am needing the internal wiring harness when I got the motor they had it pulled out. I posted the other pic showing my external wiring harness. It has 7 plugs. The internal wiring harness he showed pics of only has 6 plugs so I was thinking that would be the wrong harness I have looked at others on eBay and other website that have 7 pin plugs on the internal wiring harness 414-2770 is the number I looked up for the 7 pin internal wiring harness

 

[carholme]

Re: 50 hp thunderbolt help

414-2770 is an alternate p/n for the 52770A1 listed in the parts list.

In the link below, see that it lists 52770A1 as an OE# which is replaced by 414-2770 manufactured by CDI.

Dynamic Results

Gerry