7.5 Honda (B75)

[Skull]

The motor runs fine but will not peek out, I was thinking it might be timing or point gap.<br />Any ideas?

 

[radsrh]

Re: 7.5 Honda (B75)

What year motor are we talking? and by not peek out what do you mean? what is the wot rpm and when is the last time you ran the motor, was it running correctly then?

 

[Skull]

Re: 7.5 Honda (B75)

Its about 1975 model and I mean by not peeking out is that it seems to stop at half throttle .<br />The motor the last time I used it ran well and would get the 12 ft dingy plaining with ease but now not even close but still seems to be running ok.

 

[Yepblaze]

Re: 7.5 Honda (B75)

Pull off the carburator bowl. Remove main jet and the emulsion tube above it. Clean completely as required. May require a small probe to disloge debris from very small passages. Replace and run.

 

[trollhole]

Re: 7.5 Honda (B75)

Have you checked the shift linkage and made sure it's working correctly with the carb. Cause you know when it's in neutral it won't go above half throttle until you put it in gear. Maybe something is not adjusted right. Other thing to look for is to make sure the linkage from the fuel line connects to the houseing is pushed all the way in. If not it will only let so much fuel into the carb. To me it sounds as if the fuel pump is going or the scren on the fuel pump has trash in it. Just a few thing to check.

 

[alcan]

Re: 7.5 Honda (B75)

Skull, Try running with the bonnet removed. Maybe you have an exhaust leak.

 

[Skull]

Re: 7.5 Honda (B75)

Ok I,ve just taken the motor out for a test run and found that it is running on only 1 cylinder.<br />I checked out the compression and the 1 that is not firing is low (dont ask me what the PSI is I did a thumb test).I think its the valves not the rings because it dosent blow smoke or use oil.<br />Does anybody know how to do the valve timing and adjust the valve clearance.

 

[Skull]

Re: 7.5 Honda (B75)

are there any timing marks

 

[alcan]

Re: 7.5 Honda (B75)

Hi Skull<br /> The ole thumb test. Well I guess thats scientific enough to tell you don't have any compression on that hole. I suppose you could remove the valve cover and have a look see. You may have a stuck valve. You will have to remove the hoses from the fuel pump and four 6mm bolts to get the cover off. There has to be some where you can get a manual. Might be worth a trip to Tokyo just to get one.

 

[45_red]

Re: 7.5 Honda (B75)

Endine cold.002-.004;tdc on compression stroke, intake & exhaust should both be closed. Torque 4.3-7.2 ft.lb.s

 

[hondon]

Re: 7.5 Honda (B75)

If you look carefully at the top of your cam pulley you will see a dot, and if you look even more carefully at the engine case between the starter and that pulley,you will see a similar looking dot.Then ,on the side of the flywheel, you will see a line ,or sometimes two,but one will be stamped with a T.Remove the pull starter and line that line up with the rear boss of the starter mount.All three should line up or the one cam pulley dot should be 180 out.If so then give the flywheel another turn, then all should line up.If not ,valve timing trouble.If so , tight valves?Crappy fuel?Exhaust leak?

 

[Skull]

Re: 7.5 Honda (B75)

I still need a manual for a 75B honda twin about 1975 I think anyone got one.

 

[Skull]

Re: 7.5 Honda (B75)