Mercruiser 888 Help....I Think

[kcs1211]

First Post here, seems like a LOT of knowledge here. Sorry for whats about to be a long post, I hope someone can help.

I have a 76 21ft Glasply, with what I believe to be a Mercruiser 888, the side of the boat says 188hp, the engine valve cover says 188hp. The only tag remnant left on the outdrive says HP165? I was told by someone that did a tune up on the boat, that they believed it to be a 302 block, w/351 heads on it, he figured that due to the firing order.

The boat sat in the water for a long time, the outdrive had a lot of growth, the hull and stringers appear sound, and Im going to take on a complete resto.
My question is on the outdrive....which one do I have? Is it an hp165? or an 888? I can't find much info or parts for either drive. I am looking for a direct replacement if possible, when I pressure washed the growth off, most of the paint came with it, and with some barnacles, it is ugly. Im not sure if it could be saved, before the sitting in the water, the drive worked beautifully.

Are there alternative replacements to this drive? Can someone point me in the right direction?

The serial # I show on the engine is - 3691880 that is located on the valve cover.

Thanks for any help. I do have manuals already, just about every one I could find.

 

[ziggy]

Re: Mercruiser 888 Help....I Think

ya need to check out the sticky at the top, adults only... inside you'll find a wealth of info... check out the one on manuals, ya need #2 (confirm proper manual by s/n). it'll lead ya in the right direction...

 

[WizeOne]

Re: Mercruiser 888 Help....I Think

Might be a little premature to think about replacing the outdrive, kcs. Most outdrives get ugly on the outside, especially when they are moored, but they may be perfectly servicable on the inside. Drain the fluid and see what comes out. If it is virtually all clear, or even slightly milky, oil then you would probably be good to go. Well, you might want to change the impeller as the black anchors have puny little pumps and you do not know what it's state is or when it was last done.

btw, your 302 is a 188 hp engine. The 888 refers to the engine/drive package. Your drive is a Merc I.

 

[kcs1211]

Re: Mercruiser 888 Help....I Think

Thanks for your help Wizeone, Im very familiar with engines, as I run a shop, Im just learning outdrives.
From searching the site, it sounds like that drive is compatible with most alpha 1 mercruisers for gen 1 am I correct?

I've got all the manuals in print, but I downloaded this one as well.

Im sure I'll have lots more ??'s throughout the build. Thanks

 

[ziggy]

Re: Mercruiser 888 Help....I Think

for sure, check out the drive ya got. externals can be painted...

also when ya drain the gear lub. i feel for metal shavings, especially at the beginning of the flow. also, in the sticky. read up on pressure testing a drive. do that. also, with drive off, check yer ujoints and lub em if ok. check yer gimble brg. check alignment, lub coupler, lub gimble brg. inspect bellows, water hose, shift cable bellows, lub shift cable slide. any rust on the drive assy. ujoints or drive shaft or shift shaft. check ft. seal of drive and yoke for rust. it's all in the manual what to check for too i believe.
if the drive says 165 on it. ya'd think the drive came off a 165hp mercruiser engine, not the 188hp 888 mercruser. ya might check and see about the gear ratio. my guess would be they is different. i can't seem to find a facts right now so can't say for a fact though. the 165 is 1.65:1 ratio though. for sure id'ed by hash marks on the drive and driven gears in the upper (only 1.65:1 have hash marks per sm). yer drive should say 888 on it just like the engine. s/n? it's a mercruiser 1 drive. interchangeable thru alpha1 gen1 best i read. not gen. II though. sei makes a replacement drive that's supposed to be cool. iboats sells them i think.

 

[WizeOne]

Re: Mercruiser 888 Help....I Think

kcs, your drive SHOULD be a 1:50 to 1 drive ratio. 1:65 to 1 drives were used on 165 hp and other smaller motors.

 

[kcs1211]

Re: Mercruiser 888 Help....I Think

If it is the 1.65:1.......(it says HP165 on the side), will that hurt anything? The boat ran fine before sitting. Should I look at switching to a 1.5:1. Thanks for any help.

 

[WizeOne]

Re: Mercruiser 888 Help....I Think

If it is the 1.65:1.......(it says HP165 on the side), will that hurt anything? The boat ran fine before sitting. Should I look at switching to a 1.5:1. Thanks for any help.

The 1.65:1 would be like a lower gear and would probably not be too bad for a heavier boat. Ultimately you would want to match the potential hull speed (not easy to determine) with the maximum rpm WOT rating of the motor (probably max at 46-4800 rpm) and the speed that you can achieve at WOT with the prop you have installed.

However, I could see no evidence (in the manual) that Merc offered different final drive ratios, for a given motor, for different size/weight boats. Maybe some of the experts could weigh in here.

As a comparison, I have an 888 setup (original 1.5:1) in a fairly light 18 footer, running a 13"+x 21 pitch prop and can achieve 4600+ rpms.

 

[Bondo]

Re: Mercruiser 888 Help....I Think

Should I look at switching to a 1.5:1.

Ayuh,...

As noted by Wiseone,...
As long as you can Prop it to run the right RPMs at WOT,...

It'll be Just Fine.....

Normally, standard props are offered somewhere between 15",+ 23"....
If you need a Bigger prop, you go with a Higher gear ratio,...
If you need a Smaller prop than what's available,.. You go to a shorter ratio..

 

[MikDee]

Re: Mercruiser 888 Help....I Think

Yrs ago I had an old 18' Wellcraft Airslot bowrider, with a 302/188hp Mercruiser. I found out before I bought it, that it was originally a 165hp/6cyl Mercruiser, but the engine was swapped (upgraded). Just a heads up here, but that might be what you've got as well. It's not really a problem, it's just a bit lower geared outdrive, which only helps build torque on the 302 anyway

You can prop up to match, just keep the rpm range between 4200-4600rpm at WOT, depending on the load.

 

[kcs1211]

Re: Mercruiser 888 Help....I Think

Thanks for the help guys. I'll make sure I have it prop'd right when I get it back in the water. Im going to take the outdrive off this weekend, do the water pump and take a look inside.

Thanks again. I'll be back w/more questions.