1988 135hp rebuild upgrades wanted

[davek1]

I think I might rebuild a 1988 135hp 2 liter and wanted to know if there are any performance mods I can do? If the 135 is a detuned 150 what is the detuning? carbs timing, reeds or what, what about the heads should I have them shaved to increase compression or not, if so how much ? thanks Dave

 

[Dukedog]

carbs/tuner are tha only difference.. performance modifications for tha little motor are limited unless ya gotta bucket a cash... cutting' tha heads is justa 'bout it.. how much would be determined on present ring, cylinder health.. cuttin' tha heads may require some timing adjustment along with higher octane fuel requirements... probably only show a little bottom and mid range improvement (dependin' on boat type) with nothin' on top.. you would be ahead by savin' tha bucks and do a power head swap on down tha line... there is just not much ta work with with "bolt ons" that would show any really noticeable performance.. you can usually get 'bout tha same results by "tweakin' your set up" ie: motor height, offset, prop.. type boat is gonna play a big part also......jmo

I can say this 'cause there is not a Merc production or high performance 2.0. 2.4, 2.5 bought, built, modified, that I (we) have not owned since tha very first one in 1976 up until 2 yrs ago when I sold out.......

 

[Faztbullet]

Have port timing raised .100, 200hp exhaust divider, 200hp tuner, 200 advance module, and a set of WH-29 carbs(best) add 1 " spacer plate, will get ya about 155-160 at prop...and needs to be on a light boat!!

 

[Dukedog]

200 advance module

???

 

[davek1]

thanks for the info, I have a bucket but I think it has holes in it I keep putting cash in but it keeps getting lower. anyway I've bin looking for a donor block no luck yet. the boat is a 88 18' searay runabout with a 20" transom its new to me. I will be taking the block to the machine shop next week for a spec check and estimate.
I think one cyl will need a sleeve, what would be a fair price for that and if the others don't spec out how much should I pay for boring?
thanks again for the advice
Dave

 

[Faztbullet]

It a runabout so don't worry about hopping it up as you will need all the low end torque to ski/tube. Unless a bridge is broken or deeply grooved it can be bored .040 oversize. If it needs a sleeve find a different block..

 

[Dukedog]

thanks for the info, I have a bucket but I think it has holes in it I keep putting cash in but it keeps getting lower.
Dave

my point exactly... then ya gotta add a bunch of extra, precise machine work ta make "horse power" that takes a special kind of machinest that actually KNOWS WHAT HE'S DOIN' that ya gotta track down...if it has ta go .030 or more is when i'd be lookin' for another block.. that's pretty much a cut off spot for havin' to really look at carb jetting.....Fb and I differ a little here..i'll ask around about a block in this area.. check S&F, BBC parts threads for a block...flea bay only if its guaranteed in writing ta be whats advertised......gl

if ya decide ta rebuild and keep it do it right with all new stuff including new bores, pistons n rings are you'll be back to square one in short order if ya piece meal it.......jmo

200 module???

 

[davek1]

thanks guys just thought I would ask. I'll post the results of the inspection when completed thanks.
Dave

 

[Faztbullet]

200 module???

Late model timing advance module..thinkpart is 937 something, will get me notes

 

[Dukedog]

called a "high speed control module".. basically a "limiter".. its junk and nla.. it, like tha "idle stabilizer", are tha ones that can screw up tha timin' when it goes south.........jmo