1986 honda 100 4 stoke

[big carp]

i bought a 1986 honda 100 4 stroke motor at a garage sale. i hung it on the back of my targa to use as a kicker motor. it started 2nd pull in a barrel, but when i took it to the lake, it seemed to bogg down at full throttle. so i took off the cowling it would run perfect, it runs great at low throttle with the cowling on. i assume their is an air problem??? act like its starving for fuel, the previous owner had a new fuel pump put on it, thinking would fix the problem but it didnt, any idea's? maybe fuel connecters? on ebay i seen several cowlings for this motor for sale with holes drilled all over them. is this an issue with this model? any help woud greatly appreciated!

 

[ngt]

Re: 1986 honda 100 4 stoke

I am not an expert by any means, and really not even someone to give advice on motors period. With that said, I do have an 1981 7.5 Honda 4 stroke and just went to someone to have it looked at. He said, sometimes when your motor has a problem with the exhaust seals or that part of the motor, it kicks the exhaust out inside the motor cover, causing these types of issues. So, people take the cover off (or drill holes all over it) and the exhaust can be released, causing it to run fine again. Again, I don't know enough about motors to say it's the problem for sure, but you can check if the exhaust is coming out where it is supposed to by holding your hand back there and feeling if it's blowing out or not. Just trying to help Hopefully someone with more experience with these motors can come in and clarify.

 

[hondon]

Re: 1986 honda 100 4 stoke

Exhaust leaks on these engines were common back in the day and that sounds like thats where you may be.There is an exhaust horn at the bottom of the cylinder head that becomes corroded because of the mix of heat and water.That horn has now been updated and is much more substantial.If you run well with the cover off replace the horn and all should be well.

 

[adam1psu]

Re: 1986 honda 100 4 stoke

I am not an expert by any means, and really not even someone to give advice on motors period. With that said, I do have an 1981 7.5 Honda 4 stroke and just went to someone to have it looked at. He said, sometimes when your motor has a problem with the exhaust seals or that part of the motor, it kicks the exhaust out inside the motor cover, causing these types of issues. So, people take the cover off (or drill holes all over it) and the exhaust can be released, causing it to run fine again. Again, I don't know enough about motors to say it's the problem for sure, but you can check if the exhaust is coming out where it is supposed to by holding your hand back there and feeling if it's blowing out or not. Just trying to help Hopefully someone with more experience with these motors can come in and clarify.

Hey, Ngt how quiet is your 7.5 compared to a 2 stroke of about the same size? I am looking to get one about that same year/model and are they very reliable or as reliable as any other honda product? thanks -adam

 

[ngt]

Re: 1986 honda 100 4 stoke

Hey, Ngt how quiet is your 7.5 compared to a 2 stroke of about the same size? I am looking to get one about that same year/model and are they very reliable or as reliable as any other honda product? thanks -adam

well, I have had some issues with mine, but I think they're just normal issues. The exhaust thing discussed here, some seals wearing out, pull line snapping, etc...I am not really sure if it's louder or not that 2 strokes...as it's my first motor and I haven't been on a lot of boats. It's quieter than my neighbors 2 stroke dirt bikes, that's for sure, lol. Most people that I have talked to about these motors say they are easy to work on if you need it and pretty reliable. Mine is 1981...so that's almost 30 years old. I would expect little things to go wrong with it here and there. Might be hard to find parts or someone to work on it, but maybe not...

again, take what I say with a grain of salt. I'm new to boats and outboards.