"Bumping" 140HP Evinrude

[kid from connecticut]

I have a 1988 140HP Evinrude V4 on a 1977 19' Penn Yann. While engine is running at around 4000RPM about every eight to ten seconds it jolts or "skips". You can feel it and actually see the engine "jump". it happens at all RPM levels and seems to be getting worse. The engine keeps running and pushing the boat with no prblem it just keeps "jumping".

 

[Chinewalker]

Re: "Bumping" 140HP Evinrude

Hi Kid,<br /> The last time I saw this happen it ended up being the pinion gear going out of the lower unit. Everytime a chunk of gear got wedged between the gear teeth it would kick the driveshaft upwards and make a definite clunking.<br /> First thing I'd do is check the lower unit oil. Any evidence of metal filings or chunks would be a good indicator of gear damage... No metal filings and it's on to other theories...<br /><br />- Scott

 

[Silvertip]

Re: "Bumping" 140HP Evinrude

Spun prop hub. Put a mark on the outer part of the prop and another in line with it on the hub itself. Run the boat until you feel the bump. Stop the engine and check alignment of the two marks. If they are still lined up, the prop is ok. If not, the rubber in the hub is allowing the prop to skip. Rebuild time or new prop if thats the case.

 

[MGuckin]

Re: "Bumping" 140HP Evinrude

I had the same problem about 2 years ago with a 84 150 v6. Blown exhaust by-pass plate gaskets. Almost sounded like a miss and the motor jumped, but no noticeable loss of power. Don't even know if this applies to your motor. Don't have a manual in front of me.<br />Just a thought.