1987 etlh 70 hp issue

[panasonic]

Any chance of posting a video of this happening?

[medicineman]

This lake trip is done so can’t now. Maybe in a couple of weeks. Seems like it is running on 2 cylinders instead of 3

[zenoahphobic]

I just wonder if there is other slop in the uptake when you move the throttle forward, such as the connection on to the ignition advance lever. Could there be a moment that the ignition is retarded before advancing?

[medicineman]

Interesting idea. I have checked timing at idle and it was dead on. Even thou engine is 1987, very few hours were on motor and linkages do not show wear.

[medicineman]

got a pleasant surprise this morning and it was not raining before we left Lake. I took a quick trip and made a video. Will be happy to post if you tell me how. Thanks!

[medicineman]

I just wonder if there is other slop in the uptake when you move the throttle forward, such as the connection on to the ignition advance lever. Could there be a moment that the ignition is retarded before advancing?

I did check to see if any play and it appeared to be advancing properly. Thanks for suggestion

[medicineman]

Any chance of posting a video of this happening?

I made a video but can not seem to upload. In all honesty I am not sure audio is good enough to help anyway. Just hear engine running—not clear enough audio to really hear the “struggle” engine has until I give it about 2/3 throttle and then it kicks in and pulls fine. Like I have said already, cranks good, idles good, never cuts off backfires etc, just has an area of acceleration at less than 2/3 throttle that is sluggish and Vibrates more until it hits a sweet spot in acceleration and them purrs like a kitten. Just does not like to get the boat moving if I give it less than 2/3 throttle, but does not cut off, sputter, or anything like that.

[panasonic]

I made a video but can not seem to upload. In all honesty I am not sure audio is good enough to help anyway. Just hear engine running—not clear enough audio to really hear the “struggle” engine has until I give it about 2/3 throttle and then it kicks in and pulls fine. Like I have said already, cranks good, idles good, never cuts off backfires etc, just has an area of acceleration at less than 2/3 throttle that is sluggish and Vibrates more until it hits a sweet spot in acceleration and them purrs like a kitten. Just does not like to get the boat moving if I give it less than 2/3 throttle, but does not cut off, sputter, or anything like that.

Make a YouTube channel for yourself, very simple and easy to do, then upload your video there. Share the YouTube link here and we can see and hear it.

Have you looked at your plugs? Do they all look the same?

Seeing that spraying gas into each carb did not help when the motor was acting up...MAYBE it is dropping a cylinder...not firing or erratically firing at lower throttle positions. That is why I ask about the plugs..

If one plug is black and the other two are fine, then that cylinder may not be firing consistently. IF you have a suspect cylinder,swap coils around and see if the misfire follows by fouling that plug.

Also your plugs caps. Have you removed them and looked at the connections for corrosion and measured their resistance. The connections for the wiring to the coils secure and clean...

These are some simple things to try. Keep at it... you will find the problem.

[medicineman]

Make a YouTube channel for yourself, very simple and easy to do, then upload your video there. Share the YouTube link here and we can see and hear it.

Have you looked at your plugs? Do they all look the same?

Seeing that spraying gas into each carb did not help when the motor was acting up...MAYBE it is dropping a cylinder...not firing or erratically firing at lower throttle positions. That is why I ask about the plugs..

If one plug is black and the other two are fine, then that cylinder may not be firing consistently. IF you have a suspect cylinder,swap coils around and see if the misfire follows by fouling that plug.

Also your plugs caps. Have you removed them and looked at the connections for corrosion and measured their resistance. The connections for the wiring to the coils secure and clean...

These are some simple things to try. Keep at it... you will find the problem.

!. I will look into youtube and relisten to video i made to see if i think it can be heard.
2. have used 2 sets of plugs and both looked uniform. I also have checked compression and cylinders were less than 10 lbs apart and in the 130 range as i recall.
3. i will inspect plug caps this weekend. what puzzles me is that it fires right up, idles great, and runs great once i get past 2/3 throttle. never backfires, cuts off, etc.

[medicineman]

!. I will look into youtube and relisten to video i made to see if i think it can be heard.
2. have used 2 sets of plugs and both looked uniform. I also have checked compression and cylinders were less than 10 lbs apart and in the 130 range as i recall.
3. i will inspect plug caps this weekend. what puzzles me is that it fires right up, idles great, and runs great once i get past 2/3 throttle. never backfires, cuts off, etc.