85hp seahorse

[dukes0617]

I have a 1979 johnson seahorse 85hp v4. Runs great for the most part but sometimes loses power when driving. I keep the throttle where it was and motor seems to clean out after about 30 40 seconds then boat takes off. Almost seems like motor is loading up. If I rev in neutral it seems like it cleans out and is usually fine for most of the day but does occasionally still happen. sometimes this also happens when I am just leaving the dock like the motor is not warm enough. I have not tried anything yet. Just looking for suggestions. Thanks for the help.

 

[emdsapmgr]

Re: 85hp seahorse

Could be any number of things. You could be losing spark on one cylinder. Test the spark with an inductive timing light-that will show the spark quality on each wire. Also, you could have a weak fuel pump. When it starts to lose power, have someone constantly prime the fuel hose bulb. This will force extra fuel into the carbs. If it runs fine when doing this, likely you have a weak fuel pump. Keep in mind that your engine was made before ethanol fuels came out. None of the original fuel lines or the bladder in the fuel pump were made to work with ethanol fuels. They can deteriorate from the alcohol and cause bits of hose material to lodge in the carbs, causing running issues.

 

[dukes0617]

Re: 85hp seahorse

Thank you for your help