Evinrude XP-100 Block compatibility?

[ct1762@gmail.com]

Hi guys i'm rebuilding a 1989 gt/xp 100 crossflow and the original block is ruined. the sleeves on 2 cylinders have nicked ports and deep gouges from the ring catching, and was wondering what replacement block can be used? the 88/90 hp block has smaller ports, but not sure about the 110/115hp motors as they have a different part # for the block as well, but of course those use the bubble back exhaust and the xp/gt is a flat back. is that the only difference? i want to make this motor correct with the correct ports and heads, not just slap on any v4 block and tune from there. and i do realize i could just put new sleeves in the original block, but really dont want the extra risk involved. thanks!

 

[flyingscott]

Pretty sure that uses the 115 block.with smaller carbs and no bubbleback.

 

[ct1762@gmail.com]

awesome thanks! i'm re-doing a flying scott 60hp 59' nightmare generator model. will have to post in that section next lol

 

[racerone]

I thought the 100 gt / xp was a bubble back block !!!

 

[flyingscott]

I would listen to racer on that he has probably seen more of them than I have. I always though that the 100s were flat back.

 

[flyingscott]

awesome thanks! i'm re-doing a flying scott 60hp 59' nightmare generator model. will have to post in that section next lol[/
I have 5 or 6 of them.

 

[ct1762@gmail.com]

no the xp/gt 100 is a flat back 100% literally just got done taking the heads off to inspect damage. its a rather unique setup with a flat back and big-bore carbs 1 5/16'' if im not mistaken. im sure racer can chime in here but kind of an odd-ball v4 which is why i want to keep her original. thanks flying scott... i was going to ask how to get a voltage regulator for it as the original delco one is long gone. those pistons seem tight in their bores no wiggle at all!

 

[racerone]

Is the serial # on the block the same as the serial # on the swivel bracket, yes or no ?----Nothing unique other that marketing a 115 HP motor as a " fast " 100 HP model.

 

[flyingscott]

no the xp/gt 100 is a flat back 100% literally just got done taking the heads off to inspect damage. its a rather unique setup with a flat back and big-bore carbs 1 5/16'' if im not mistaken. im sure racer can chime in here but kind of an odd-ball v4 which is why i want to keep her original. thanks flying scott... i was going to ask how to get a voltage regulator for it as the original delco one is long gone. those pistons seem tight in their bores no wiggle at all!

Your.Scotts have a 59 Delco voltage regulator same as a car. The generator is also a delco straight from GM cars only difference is it is also the distributor. Make sure.you flash.it.

 

[ct1762@gmail.com]

Is the serial # on the block the same as the serial # on the swivel bracket, yes or no ?----Nothing unique other that marketing a 115 HP motor as a " fast " 100 HP model.

Yes Racer both are the same. blocks original. the interesting thing, and why i called it an "odd ball" is the carbs are not jetted the same as a pre-1986 115hp (as thats a flat back, figured its what the gt100 is modeled after). the gt100 uses 60c high speeds, and the 115 used 67's. also, no extensions on the gt-100 air silencer, but all the other models, including the 115 have airbox extensions. ill grab a used 115 block and just hope ports are the same i guess!

 

[racerone]

What is the model # of your XP / GT motor ??------What size are the intake ports on your GT / XP model ?

 

[ct1762@gmail.com]

its an E100STLCEM. i've never measured ports before... you mean just take an inside micrometer and measure? ill do the same for the carbs too