70 HP johnson running bad

[afojc]

I can't keep my 70 horse johnson running right, it is worse when drive is engaged, also there is a strange noise coming from the lower end, but only when drive is engaged. Thanks in advance and God bless.

 

[tashasdaddy]

Re: 70 HP johnson running bad

Welcome to iboats. What year and model number?what have you checked. lower unit oil? compression, spark, fuel delivery, air leaks in fuel line, water in gas. when were they carbs last cleaned and rebuilt. are the coils dark and cracked?????????

 

[afojc]

Re: 70 HP johnson running bad

It ran fine last season when I winterized it, It has fresh gas/oil mix, the plugs are OK, someone suggested that perhaps the carbs. are gummed up and that the only way to clean them is to take them apart and clean them. The lower unit noise is kinda like a slight knocking that gets faster as the RPMs increase.

 

[F_R]

Re: 70 HP johnson running bad

That lower unit is bad news if it is like you say. You shouldn't be able to hear anything from it. Don't bother with the rest of it till you do a complete evaluation of the whole motor to see if you have anything worth fixing.

 

[bgphill]

Re: 70 HP johnson running bad

If you hear the knocking only when you're in gear then have that lower end looked at. If you hear knocking when it's out of gear then you may need a power head. If you think it's the power head, try a decarb and see if that clears the sound and improves the performance. Before you do any of that though, check your compression or take it to someone and have it checked. You may have a stuck ring.

 

[afojc]

Re: 70 HP johnson running bad

It only makes the noise when it is in gear and gets faster as you give it more throttle.

 

[Lodgepole]

Re: 70 HP johnson running bad

Get the lower unit thing corrected first before you really tear something up. Sounds like gears or bearings. Then see what you've got upstairs.