'89 88hp rude missing?

[FreeBeeTony]

I recently replaced the water pump and thermostats on my '89 88hp evinrude and installed a temp gauge. Went out yesterday and the motor ran great (~140 deg) and was pumping nice! When at the end of my return trip while slowing down it felt like the engine misfired....almost like I hit something. I put it in reverse in case of weeds........then accelerated hard (in fwd) with no problems.....while slowing down I felt the same 'shake'. Does this sound like a possible lower unit problem? Or would I feel the shaking when accelerating?

 

[FreeBeeTony]

Re: '89 88hp rude missing?

Spoke with a friend about this and he said I might have a lean mix problem when backing off on the throttle.......does this sound like a possibility?<br /><br />Thanks

 

[FreeBeeTony]

Re: '89 88hp rude missing?

 

[12Footer]

Re: '89 88hp rude missing?

When you have the boat on trailer, rotate the prop by hand,and keep your eye on the center,or cone area. If there is any run-out, you have a bent prop shaft.<br />Inspect the blades for major dings.<br /><br />If the propshaft and prop look good, have you inspected the lower unit lube condition recently? If not, drain it, inspect the lube, and refill using new gaskets on the vent/fill screws.<br />If there are no signs of water contamination, and there are no metal chunks in the old lube, run a compression test, as it may have a low one..This would cause a vibration,even if the jug was still firing (less power developed).<br /><br />Passing all the above,<br />Check for fire on all cyclinders by pulling the plug wire one at a time.Insulate yourself and a plug puller from the plug extremely well, as the spark can jump an air gap of 1/2" !!<br />Also,make the pull-off as short as possable, as CD damage can result from an open condition at the HV output in short order....Wouldn't want to see you blow the pack.<br />The RPMs should drop-off noticably..If it stays the same, that cylinder isn't firing.

 

[MGuckin]

Re: '89 88hp rude missing?

If I may add?<br />When doing the plug spark test, use a known good plug. Makes no difference what type as long as its good and keep it close to a ground source when checking arc. Better to test it with a load than without one.<br />edited: I should have read thread better. Wrong test.

 

[FreeBeeTony]

Re: '89 88hp rude missing?

12footer..if the prop shaft was bent, wouldn't I feel it when I accelerate hard out of the hole?<br />Anyway.....I will check it right now....<br /><br />Thanks

 

[FreeBeeTony]

Re: '89 88hp rude missing?

Just checked the prop shaft, if there is any run- out it's very minimal....I don't think I saw any.

 

[FreeBeeTony]

Re: '89 88hp rude missing?

How bad would the shaft have to be bent in order to cause a problem?