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Questions about Honda 7.5

D

Doug Follett

New member
I just purchased a sailboat that has what appears to be a 1975 Honda 7.5 motor (serial # B75-2007400) that is in need of a going through. I'm a complete Outboard Newbie but have plenty of experience working on old Honda motorcycles of the same vintage. My main question is, should I try and get this motor running and use it or should I spare myself the pain and trouble and get something newer? I was told that it runs but from the looks of it, someone left the lower end in salt water for a while as it is a lot of corrosion and has bad pitting. I have been searching the Internet for parts and information without much luck. Any leads to parts suppliers, advice or thoughts in general would be appreciated. I want a reliable motor for this boat but don't want to go broke getting one.

Doug
 
Don't know where you are but out here on the "left coast", California, these old Honda's go for a premium because they are such good stuff. Especially the longshafts for sailboat kickers.

It is too bad though that many are left to rot the lower end in salt water on the backs of these boats. Because, case extensions and gear boxes from suppliers like boats.net are cost prohibitive to replace.

But, if you can pull it out and see if it will clean up, you can do some reliable patching with fiberglass cloth or even epoxy and Bondo for just pitting. As long as the housing is sound and can accept new seals, it can be repaired and put back in service. The internals don't cost too much to resurrect one and if an older one has parts listed as "unavailable" or "obsolete" they can often be found on some of the 1990's parts lists. The ignition coils come to mind as an example.

One in decent mechanical and cosmetic shape, out here, can fetch upwards of $700 which is less that 1/2 price from a new 4 or 5 hp from Mercury or Honda or...? And, there are quite a few for sale each month if you live in SoCal and are willing to take a drive to pick one up.

I also see them being sold in pieces on ebay from time to time and the housing parts can be fairly reasonable if you jump in and bid.

They are pretty easy to work on but get the HelmInc. shop manual if you decide to do the work. Around $30

Here's the page to start looking

http://www.boats.net/parts/search/Honda/Outboard Engine/0/parts.html

Your motor will be listed under the 75HP banner as they screwed this page up and refuse to fix it. I don't see your serial number but maybe HONDADUDE will see this and help you figure it out exactly.

Bottom line? if you worked on bikes and can do a compression test, are proficient using a multimeter and know what PB BLASTER is, you can work on these no problem. Just get the shop manual and clear off some bench space. If not, I buy old, not running Hondas to turn 'em around and put 'em back out there. As do many other guys that get there before me!:)
Good luck and welcome to the forum.
 
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Thanks for the reply and warm welcome. I started the motor up today so it can't be too far gone. I didn't run it long because the gas is probably five years old but it started on the third pull and seemed to want to run but I shut it down figuring I had better not get too carried away before I check things out more thoroughly and change the fluids. I'm pretty sure it's a 1976 as there was one on YouTube that looked just like it.

http://www.youtube.com/watch?v=_RfllU7Efoc&feature=fvsr

The serial number is B75-2007400. I did look under the 75 HP section but I'm still confused as to which motor is mine. What I'd really like to know if this lower unit on eBay will fit on my motor. It says it is off of a mid 1980s 10 HP but will fit a 7.5 HP.

http://www.ebay.com/itm/120836600994?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648
 
Thanks for the warm welcome and information. I actually got the motor started yesterday but shut it down as soon as I saw it was going to run as the gas was years old and the fluids need to be changed. I found where they hide the older 7.5 parts but the ones listed don't match my serial number. I found two numbers on the motor one is B75-2007400 on a plate on the outside and it was repeated again stamped into the motor. I also fond this lower unit on eBay - Item number 120836600994. It's came off of a mid eighties 10 HP and the seller says it will also fit a 7.5. I'd buy it if I knew if it fit as mine is badly pitted and has a crack or two (still holds oil). I'm pretty sure my motor is a 1976 as I have seen photos of them that look exactly like it. http://www.youtube.com/watch?v=_RfllU7Efoc
 
Sorry for butting in...but the motor is a 1973. Its model number is B75K1. It was the first 7.5 that Honda sold in the US.

I would proceed with caution when buying a lower unit for this model. The B75k1 thru B75k3 have many unique parts compared to the later 7.5 - 10 hp versions. You can double check the part numbers on boats.net to be sure.

Mike
 
Just checked out the Youtube link. If yours has a carburator like the one in the pictures, it is definitely in the K series. Notice the intake is on the top of the carburator. All the 7.5's after that have an the intake in the front.

Mike
 
The reason I thought it was a 1976 was because someone said that the year was stamped on the spark plug wire. I did find a small "1976" stamped on the top plug wire. The air intake is on top of the carb. How do you come up with B75K1? is that on a chart somewhere? It's probably very similar to the Honda motorcycles. They also had a "K" series back in the early '70s There is a chart that is readily available that gives you the year of your bike by the VIN # on the frame. Is there such a chart for their boat motors as well?
 
I can not explain the 1976 on the plug wire. I looked it up by serial number in the Honda Outboard Rigging Guide that all Honda Dealers have.

Mike
 
The B75k1 was made from 1973 - 74
The B75k2 was made from 1975 - 76
The B75k3 was made in 1977

It is probable that the parts will interchange. As I said before, be sure to compare the part numbers on boats.net to be sure.

Mike
 
Is there a chart somewhere that I can download that shows the serial numbers in relation to model and year? My motor has the intake on top of the carb.
 
Hello,

I have one of these outboards as well. I do not have the exact model number or serial but I'm thinking it is a B75k1 series outboard. Has anyone out there been able to find parts for these older 4 stoke Honda outboards. I'm looking for basics parts such as carb rebuild kits, lower unit impellers, plugs, coils, any other types of parts would be helpful. Thanks!
 
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