88 Mariner 90hp no power UPDATED

claytonr1973 · #1 June 5th, 2008, 08:56 AM

Took my boat out about a month ago after winter storage and was running fine for a while then started bucking at full load. I replaced fuel filter and then it wouldn't go obove 3000 rpm and had no power. I Rebuilt the fuel pump and put another filter on and still no power and wont go above 3000. Pulled all plugs and have fire, drained and purged the carbs, and checked the throttle thinkage and everything is fine. This boat use to fly and now it barely has enough power to get on/off the trl. It takes a while to get it to idle when first started but you can get it to rev with the idle throttle but when put in gear it just won't do anything. Any help would be appreciated as I really don't want to spend alot to fix this. Thank you.

CharlieB · #2 June 5th, 2008, 04:45 PM

Search this site FAQ's for spark test and re-post with your results

DO NOT start buying electrical parts until you have tested and verified any fault as there is NO RETURN on electrical parts.

claytonr1973 · #3 June 15th, 2008, 10:14 AM

Took the boat in to get the carbs cleaned as it passed every other test. Ended up having some trash in one of the reeds. I haven't had a chance to test it yet as we have been flooded and the river is running FAST and will wait for better conditions to test, though shop said they tested and it waqs fine. In their initial diagnosis they checked compresion and it was 95/100/95. Is that bad and would the trash in the reed affect the compresion test? This boat(18ft semi v alumaweld fully loaded) flat out flies. It sure don't act like it's low on compression. Also my tach quit working and he said it needs a new rectifier and it cost $150. Can I get that cheaper online? Maybe one of the sponsors of this site? Thx.

Chris1956 · #4 June 15th, 2008, 10:42 AM

Your compression is fine. Junk in the reeds is unususal, and could affect compression test results.

You may have a voltage regulator or a rectifier, depending on the year and model. Look up the motor by year and model on dougrussell.com or crowleymarine.com, and get the part number of the VR or rectifier. CDI.com wil likely have a better replacement part than Merc.