Any Options for an older V-6 Johnson?

[LSaupe]

I have an older ('85) V-6 150 Johnson on the back of a V-King. I would like to be nearer to the hull rated 175 HP. Are there any reasonable mods I can do to this engine to bump it up a bit. It is a solid low hour engine just needs a bit more grunt.

Larry S.

[Action Dave]

What's already been done to it?

[hsbob]

if its still the motor rated hp [and i think it is] the only difference between the 150 and the 175 were the carb. every other part is the same even the blocks carried the same omc part number. in 87 the carb were 235 each.

al stoker is the omc builder.

[Lockjaw]

Find a 235 and put it on there, with the 150 cover. :D

[EMDSAPMGR]

There were two types of 150's in 1985. The base model, and the XP/GT version. The XP/GT model has been modded by the factory and has some nice goodies already installed. Which version are you starting with? Your model number will be either X150SXX or X150TXX. The high perf one is the 150S model. You won't be able to run a 235 powerhead unless you change out the exhaust adapter. What compression does the engine make currently? There are a number of things you can do, even to the 150S.

[ShaneBarron]

Find a 235 and put it on there, with the 150 cover. :D Been there...Done that!

[LSaupe]

Currently on the road and just now getting connectivity. Thanks for the replies.

Nothing has been done to the engine. Unfortunately I do not have the engine number with me but will check next week when I get back.

[LSaupe]

Turns I have the 150T model. Bone stock and runs nice. Unfortunately cant get a comp test until spring when it comes out of storage.

Any more thoughts on what it would take to bump this up 20 HP or so?

Thanks and Regards,

Larry S.

[dynobo]

Your 150 is the standard model. Find a 150/175 GT or 235 and get the carbs off them. Yours are probably 1 1/4 where the GT/235 are 1 3/8 diameter. Also swap the heads off the GT motor if it is a 150. The 175 GT and '80 and later 235's were 2.6 litre not 2.5 litre as you have. I have also seen increases with adding Boysen reeds to the crossflows. They hardly ever add increases to top end but My opinion is they do with crossflows. With these additions you should be in the 170-175 range.

[Lockjaw]

I would do intake reed filler blocks and the reeds.

You should be able to come up with a used set of the filler blocks, if you add reeds, these would go right in easily. That ought to help response.

[Forkin' Crazy]

There were two types of 150's in 1985. The base model, and the XP/GT version. The XP/GT model has been modded by the factory and has some nice goodies already installed. Which version are you starting with? Your model number will be either X150SXX or X150TXX. The high perf one is the 150S model.

So what are the goodies? Mine had 1 5/16 carbs, but that's all I really noticed. Some one had already robbed the heads and left a damaged (one of them) early set. I was toying with the idea of bringing it up to 200 port specs, 1 3/8s carbs, scaloping the pistons and cutting the lower intake side of the block. I think it had tighter lower mounts too.

[Forkin' Crazy]

There were two types of 150's in 1985. The base model, and the XP/GT version. The XP/GT model has been modded by the factory and has some nice goodies already installed. Which version are you starting with? Your model number will be either X150SXX or X150TXX. The high perf one is the 150S model.



So what are the goodies? Mine had 1 5/16 carbs, but that's all I really noticed. Some one had already robbed the heads and left a damaged (one of them) early set. I was toying with the idea of bringing it up to 200 port specs, 1 3/8s carbs, scaloping the pistons and cutting the lower intake side of the block. I think it had tighter lower mounts too.


:confused:...............

[Six Four]

Greg Rothwell (Hydroballistics) @ Rothwell marine in Hope Arkansas has a 85 Gt 150 he is going to part out if this helps anyone..

[Charlie M]

If you want any of those 1 3/8 carbs, or high compression heads for those crossflows just IM me I have mess of them cheep!

[LSaupe]

Charlie:

Tried to send a PM but get an error message. Looks like your inbox is over its limit per the message.

Upon 2nd check looks like I have an '84 (not sure if that makes a difference or not). Model: J150TLCRD Ser: J5968311

If you have a set of 1 3/8 carbs (3) that would fit this engine please shoot me a PM (with $$$ info). Also, if you have a set of higher compression heads for that engine as well please shoot me that as well.

Thanks to all who replied here.

Happy 2007!!

Larry S.

[EMDSAPMGR]

Any 150 GT/XP crossflow has upgraded components from a stock engine: different heads, larger carb throats, the cowl intake vents, stiff engine mounts, and the 35 amp alternator. Some had higher factory timing also. If you are looking add bolt-on hp to one of them, add the intake filler blocks (322722 -NLA) and upgrade the heads. A number of good heads are still around, IE: the 79 235 heads (323872 873) or the 79 200 heads (323456, 457). It would be rare to find a set of 76 200 heads (320644, 643). If you want to get into machining, square off the intake and exhaust ports. Cutting the block intake runner and the piston skirt would probably only provide added hp if you also added the tuned (bubble) exhaust like the 235's. Adding a set of composite reeds is always a good upgrade, too.

[Lockjaw]

Yeah the reeds, intake fillers and compression help alot. It made a huge difference on my GT175, like about 5 to 6 MPH, and alot more punch.

Just be sure to get ball park jetting specs if you raise the compression, or else it will be a very short lived engine. Racer can probably get you very close.

[Cobra1racer]

Swap out my 185 power head. Sucker runs great. Just not as Fast as the 300GT I just bought.

[Forkin' Crazy]

Thanks EMDSAPMGR. :)

[LSaupe]

Thanks for all the input guys. heck with all this weather in the Northeast it might be time to put this stuff back in the water!

Larry S.

[DoferGofer]

If you want any of those 1 3/8 carbs, or high compression heads for those crossflows just IM me I have mess of them cheep!
Do you have any filler blocks to fit a 1985 XP150?

Regards,

Melvin

[Forkin' Crazy]

Do you have any filler blocks to fit a 1985 XP150?

Regards,

Melvin

I was going to make a mold and make them out of urethane, but racer said you can make some by cutting some hose lengthwise so it will fit in the cavity between the cage and the intake.

[DoferGofer]

That is good to know. Thank you sir.

[EMDSAPMGR]

Contact these guys for the intake filler blocks: BOAT-RECYCLERS-OF-WILMINGTON. You can find them on the web. They tear down tons of engines and ususally have these available for sale. They will take your credit card over the phone and ship the same day. I have purchased a number of sets from them.

[DoferGofer]

Thank you sir.