Buying a used boat with a GT 150 Johnson

[RobbyA]

I am looking at buying a F/S with an 89' Johnson GT150. I am wondering if there are any reliability issues or problems with getting parts for the motor.
It seems like a lot of the parts are obsolete for this motor which has me a little leary of wanting to purchase this boat.
Any feedback would be greatly appreciated!

 

[jonesg]

Re: Buying a used boat with a GT 150 Johnson

Theres a ton of used parts around, they made the V6 by the thousands.
The most commonly serviced parts are made by other companies such as Sierra and CDI. Mallory is another part supplier.
CDI elec parts are better than factory.
I have a 1994 150hp.
Also have a 1959 10hp that I just bought new coils, points and plugs.

When theres a lot of engines still in use the 3rd party suppliers keep making parts. Anything like a crankcase can be had on craigslist or ebay.
I just saw a 150hp parts engine for $400.

You can find all the common service parts for that engine right here on iBoats.

Seriously, do you consider whether you can still get a driveshaft for a pickup truck if you're considering one?

I drive an old volvo, the factory hasn't made mechanical parts for 15 years.
But ya can get any part needed.
The biggest reason to get a Johnson is the expert help here.
...as long as you know what to watch out for when buying.

 

[RobbyA]

Re: Buying a used boat with a GT 150 Johnson

...as long as you know what to watch out for when buying.

How do I know what to look for besides the obvious.

The gentleman has offered to take me to the lake and let me run it.

I was going to look at it when I had a chance, but his brother had it at the lake skiing with his kids.
So now I wait until next Wednesday to go look at it.

 

[wilde1j]

Re: Buying a used boat with a GT 150 Johnson

Running it under load as you're planning is the only way. Also, I would check compression for all cylinders and drain a little gear oil from the bottom plug to check for water looking for any sign of water (milky gear oil).

Motor should accelerate to WOT w/o hesitation and idle smoothly.

Test choke/primer operation.

Shifting should be w/o any unusual noises. Test reverse as well. Also cycle trim and tilt ... should operate w/o any unusual noises.

No problems, as already pointed out, getting any parts for this motor.

 

[RobbyA]

Re: Buying a used boat with a GT 150 Johnson

Thank you for your replies.

To check compression, do you do it like on any automobile? Remove all plugs and spin it with a compression gauge hooked to one cylinder, move to the next and rinse and repeat?

 

[wilde1j]

Re: Buying a used boat with a GT 150 Johnson

Correct ... you want all holes within 10% of each other.

 

[RobbyA]

Re: Buying a used boat with a GT 150 Johnson

Bought the boat yesterday. Motor seems to run smooth but idles really low. Sometimes putting it in gear it dies and it seems like I am missing another 500 RPM on the top end.

Is there a way to idle it up a bit? I am not worried about the top end until I get the TACH working. By the way the TACH doesn't work any quick advice on wiring to see if it is wired right. Its an 185 Cajun Espirit with the 150 GT Johnson if that helps.

 

[wilde1j]

Re: Buying a used boat with a GT 150 Johnson

Bought the boat yesterday. Motor seems to run smooth but idles really low. Sometimes putting it in gear it dies and it seems like I am missing another 500 RPM on the top end.

Is there a way to idle it up a bit? I am not worried about the top end until I get the TACH working. By the way the TACH doesn't work any quick advice on wiring to see if it is wired right. Its an 185 Cajun Espirit with the 150 GT Johnson if that helps.

How could you possibly know you are missing 500 RPM at the top w/o a working tach?

Tach requires three wires connected:
purple - switched 12vdc
black - ground
gray - sensor