20 hp mariner need help

[mikemetz]

Ser # 0A956190,, Can't get the lower cyl to run, top cyl is good. Compression is at 120 on both. Spark reserve is 1/2 or better. Have changed the lower seal and reset the reeds. Looking for other ideas

 

[gm280]

Re: 20 hp mariner need help

First of all welcome to iboats :welcome: good having you aboard...

I'm not sure I understand what you're saying about the spark. What is "Spark reserve is 1/2 or better"? Are you saying that the spark jumps a 1/2" gap? Do you have proper spark to both cylinders? And if so, is there gas getting to that lower cylinder? If that answer is yes to both questions, it should be running... Also what is reseting the reeds? Never heard anybody say that before either... Reeds are either working or not. They either open with vacuum and close with compression or they don't. So maybe a little clarification and some pictures would be great... One final thought, is this a single carb or two? If two carbs the carb feeding the lower section need attention...

 

[mikemetz]

Re: 20 hp mariner need help

First of all welcome to iboats :welcome: good having you aboard...

I'm not sure I understand what you're saying about the spark. What is "Spark reserve is 1/2 or better"? Are you saying that the spark jumps a 1/2" gap? Do you have proper spark to both cylinders? And if so, is there gas getting to that lower cylinder? If that answer is yes to both questions, it should be running... Also what is reseting the reeds? Never heard anybody say that before either... Reeds are either working or not. They either open with vacuum and close with compression or they don't. So maybe a little clarification and some pictures would be great... One final thought, is this a single carb or two? If two carbs the carb feeding the lower section need attention...

Thank you for your answer. Resetting the reeds consists of fully cleaning them and removing any debris and contaminants like from the insulation that has been sucked in over time. Spark reserve is the jump of a gap. It is getting fuel as the plug has come out wet but no evidence of fire. Water tested today and got is to fire some at high speed (wot) but even then was erratic. The 20 mariner is a single carb model. that is the perplexing problem has everything to run on both but won't fire bottom cyl with regularity. Have replaced switch box and trigger and coils so it should run but won't run roperly on bottom cyl.