90 HP Nissian low power

[gdoss]

I purchased this mode 90A in May Ran it several times and ran great. Pulled out of water in July. Ran it on cuff a couple times. Put in water yesterday. Put in fresh gas and half can seafoam. Will not plane up easily and only turns about 4000 rpm. After about 15 minutes it all of a sudden kicked up to 5300 and ran like it should for a couple of minutes. Slowed to turn and never got above 4000 again. Ran about 10 minutes. Does not skip, just loads up. I would appreaciate any info
Thanks

 

[gdoss]

Re: 90 HP Nissian low power

Sorry I can't spell too good. Trying to get used to using a laptop

 

[pvanv]

Re: 90 HP Nissian low power

Is this an old NS90A? Sounds like fuel starvation of one sort or another, but could also be dirty plugs, either from use, or from weak spark. Double-check oil mix ratio. Verify all fuel lines -- drawing air into the fuel stream is one possibility. Check for crud in carbs, etc. Inspect plugs for proper color. If they are fouled from use, try a fresh set of plugs.

 

[gdoss]

Re: 90 HP Nissian low power

Yes a NS90A, Will try plugs first. Old ones were greasy looking, but not much wear. Will check fuel lines, then carbs if necessary.
Thanks Will let you know

 

[gdoss]

Re: 90 HP Nissan low power

Re: 90 HP Nissan low power

Today I changed plugs and checked gas lines. Afterward I took her out and she ran just like before. Started checking fire. When I probed top and bottom plugs it bogged the motor down, but the center plug would show little or no effect on the running. I pulled the plug and it showed fire when grounded. It shocked me pretty hard, so I think it is strong fire to the plug. What do I check now? Don't have a compression tester. Any help is appreciated.

 

[pvanv]

Re: 90 HP Nissian low power

OK, so preliminary testing you've done indicates a problem with #2 cylinder. From your description, spark may be OK. Check carb, reeds, and compression. A Factory service manual (from any Tohatsu/Nissan dealer) would help you a lot.

 

[gdoss]

Re: 90 HP Nissian low power

Checked compression and 125-130 on all three. Probably fuel problem. Will check carbs next.
Thanks