motor hop up

[dbagwell86]

I know most of you are mercury guys but I have a 86 johnson gt 200 and wanting to make more power out of it. It's the 2.7L, so far I have only drilled exhaust and opened vents and flipped them around on the cowl for more air, I have it down now putting new stator on and fiber reeds. While I'm at it I want to work reed cages and shave heads but know how much I need to cut and what a safe compression ratio is on 93 octane, right now my comp. is 100 lbs on all cylinders. If any one knows any other hop ups or tricks with exhaust tuner, intake manifold, or carbs just let me know, I already know I'll have to fatten up on the jets. Any help at all will be great, just dont say get 280 merc. I've had the motor for a long time on my old procraft and love it, just want a little extra. It's on a light hull, 600lb 17ft xst. thanks

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[albypine]

i am sure the omc boys will see this thread and chime in. Compression would be a great start.

[JohnR]

I know that on the later motors like my 3.0 200hp you can put a set of bigger carbs on from a 225. From what I was reading here the 200 and 225 were the same just different carbs.

[phil blomquist]

I would start with what you do have before shaving the heads list which heads they are post it on here also which carbs are on it number on one of the sideplates on one of the top carbs and post that also this motor could have some of the best omc had to offer

[NosBoss]

I thought the '86 200's were 2.6 and the 87 200's were the 2.7. The 86 and 87 225's were both 2.7. I know these motors were pretty good from the factory. My 87 has a factory gutted airbox. I'm curious to see the difference you get with the new reeds. Its on my to-do list.

[dbagwell86]

My heads are the original 86 200 2.7 heads, the good ones, and carbs are the big bore ones. 85 was the last year for the 2.6 200s, mymotor looks like a 3.0l from 88 up but its the 2.7 like your 86 but with larger bore carbs, when i say i want more power dont think the motor is a slug, on the allison its a beast now, just want more. thanks guys for fast reply, anymore info will be great

[phil blomquist]

if you want to swap heads i have a set already milled .59 chamber depth do not mill those heads too many have already been molested dont do it! have someone like racer do some finger porting for you if you want to wake that thing up your compression is low there is nothing wrong with those heads!

[Forkin' Crazy]

I thought the '86 200's were 2.6 and the 87 200's were the 2.7. The 86 and 87 225's were both 2.7. I know these motors were pretty good from the factory. My 87 has a factory gutted airbox. I'm curious to see the difference you get with the new reeds. Its on my to-do list.

Nope. The 86 2.6L were 175 crossflows. The 200-225 were 2.7 loopers. Check this out. Good for reference. I compare a lot of years to see what part numbers coincide and what ones differ.

http://epc.brp.com/SiteMods/BRP_Publ...3-2ce481430299

I hear the later mid bore carbs are the best all around. At least that is what I've been told. I just bought a couple (motors with them) so I'll soon find out.

[NosBoss]

Nope. The 86 2.6L were 175 crossflows. The 200-225 were 2.7 loopers. Check this out. Good for reference. I compare a lot of years to see what part numbers coincide and what ones differ.

http://epc.brp.com/SiteMods/BRP_Publ...3-2ce481430299


I hear the later mid bore carbs are the best all around. At least that is what I've been told. I just bought a couple (motors with them) so I'll soon find out.

This is an old thread brought back to life. I've been doing lots of research lately to figure out what I have. My '87 has mid bore carbs on it, but they are the ones correct to the year of the motor. The only issue I have with them is the warped carb bowls that leak. Another issue that I need to solve this winter. Lol

[johnboy 88 vegas]

The only issue I have with them is the warped carb bowls that leak. Another issue that I need to solve this winter. Lol

Take off the bowls and flip them upside down on a wooden table. Heat them with a heat gun while pressing down on the bottom of them with a block of wood. Sometimes have to put a shim under one end to get all of the bow out. Make sure to check the jets for tightness when done.

[phil blomquist]

you can get replacements brand new or used too

[Forkin' Crazy]

This is an old thread brought back to life. I've been doing lots of research lately to figure out what I have. My '87 has mid bore carbs on it, but they are the ones correct to the year of the motor. The only issue I have with them is the warped carb bowls that leak. Another issue that I need to solve this winter. Lol

OOOPS! Sorry about that! Like that's never happened before. My buddy is a looper fanatic and likes the 98 and later mid bores with the adjustable idle needles. I would kill for that at times with my Xflow!

[bstream97]

another question, i have a 1990 225 looper is it 2.7 or 3.0, has fat head gaskets and lower(even 90lbs) compression, is this motor worth doing any mods to , its clean and runs good , also its really quiet but looks to have factory relieved exhaust at bottom of mid . thanks

[ar300johnson]

you need 140+ lbs of compression, a good set of reeds, you need to jet it safe but not fat. Be sure that timing is right on all cylinders and that you do not have any fuel restrictions and run good non ethanol premium fuel. make sure that your setup is good. setback, prop, engine height. then, if you want more hp, get out your wallet and send the block to monty or racer and get them to port block, pistons, work on intakes, etc. your budget is your limit. good luck, have fun and be safe.

[dbagwell86]

thanks, that was the answer I was looking for, do you think I can get that much compression with just shaving heads. I know I'm asking alot of questions but I'm new building 2 strokes.