90 hp yamaha 2 stroke need help with wot!!??

[THE OPERATOR]

Re: 90 hp yamaha 2 stroke need help with wot!!??

Ok, when I rebuilt the engine i reused all of the gaskets on the intake side and I made some for the exhaust side including the ones forthe cooling water. I used some gasket material I bought from the auto parts store. Should I go ahead and replace them with the right ones?? could I be getting water in the cyls and causing the engine to miss and not achieve WOT??? when I run the engine on the ears in the yd it sounds ok but when I put it in the water it seems to act like it has a miss or something.

 

[Gene22560]

Re: 90 hp yamaha 2 stroke need help with wot!!??

I had a 110 mercury that had the same issue fought it spending money on coil packs and dozens of other items. turned out to be a tach wire going to the tach from the engine grounding out. Motor would idle great and run good on the hose but wouldn't break plane on the water. Unhooked the tach wires (Tach didn't work when I bought boat)at the coil pack running great ever since.

 

[199675hpforce]

Re: 90 hp yamaha 2 stroke need help with wot!!??

You have looked alot of stuff over. Let's keep it easy how about pilot screw adjustments? Spec is 1 1/2 turns out that's 360 degrees plus 180. Then go clockwise 1/4 turn and test it! I do not see how tach being hooked up would affect performance. That signal wire green or grey on OMC has AC current. Also on your motor check to see if oring is installed for quick fuel hookup. If not you could be sucking air.

 

[SalmonSlayerr]

Re: 90 hp yamaha 2 stroke need help with wot!!??

Ok, when I rebuilt the engine i reused all of the gaskets on the intake side and I made some for the exhaust side including the ones forthe cooling water. I used some gasket material I bought from the auto parts store. Should I go ahead and replace them with the right ones?? could I be getting water in the cyls and causing the engine to miss and not achieve WOT??? when I run the engine on the ears in the yd it sounds ok but when I put it in the water it seems to act like it has a miss or something.

Did you ever get your motor fixed? I am having similar problem on my 70 hp yamaha. I am waiting for the carb kit and new fuel pum to come in the mail. If you figured out what was wrong could you let me know? Thanks

 

[robert graham]

Re: 90 hp yamaha 2 stroke need help with wot!!??

Did you ever get your motor fixed? I am having similar problem on my 70 hp yamaha. I am waiting for the carb kit and new fuel pum to come in the mail. If you figured out what was wrong could you let me know? Thanks

My 2nd on this!....I'm real interested to find out what was wrong. Thanks!

 

[THE OPERATOR]

Re: 90 hp yamaha 2 stroke need help with wot!!??

Thanks to all..

 

[THE OPERATOR]

Re: 90 hp yamaha 2 stroke need help with wot!!??

I put new plug wire caps on this weekend and new gaskets on the head and exhaust side. put the boat in the water and it seemed to get up on plane alot faster and better but still not 100 % only about 80% boat ran with two people and cooler with 40 lbs ice and drinks at about 3800 to 4000 rpm and 27 to 28 mph according to GPS. Still having a WOT problem and a intermittent MISS at lower rpms and idle. Did run a new compression test after installed the gaskets and was able to get 94 to 98 on all three. I also purchased a clymer service manual for this motor and have performed all elec tests and other tests as described in chapter 3 [ trouble shooting]. I am almost at witts end with this thing I am spending $100 to $200 every weekend on misc parts. think I am going to take it to Yam shop and let Tech put test prop on it and see what the heck is wrong. I know it is going to be something so simple I am going to want to choke something. I will advise all when I find something out this has been a real puzzler.

 

[99yam40]

Re: 90 hp yamaha 2 stroke need help with wot!!??

it is always better to test everything you can and then replace parts as needeed

 

[SalmonSlayerr]

Re: 90 hp yamaha 2 stroke need help with wot!!??

I put new plug wire caps on this weekend and new gaskets on the head and exhaust side. put the boat in the water and it seemed to get up on plane alot faster and better but still not 100 % only about 80% boat ran with two people and cooler with 40 lbs ice and drinks at about 3800 to 4000 rpm and 27 to 28 mph according to GPS. Still having a WOT problem and a intermittent MISS at lower rpms and idle. Did run a new compression test after installed the gaskets and was able to get 94 to 98 on all three. I also purchased a clymer service manual for this motor and have performed all elec tests and other tests as described in chapter 3 [ trouble shooting]. I am almost at witts end with this thing I am spending $100 to $200 every weekend on misc parts. think I am going to take it to Yam shop and let Tech put test prop on it and see what the heck is wrong. I know it is going to be something so simple I am going to want to choke something. I will advise all when I find something out this has been a real puzzler.

Thanks, I hopew ya get it running back at 100% and please keep us posted as i have similar problems.

 

[mphelle8vld]

Re: 90 hp yamaha 2 stroke need help with wot!!??

I've been following this thread but have no experience with the 90hp. It does seem like your original compression numbers of around 105 and now in the 90's seem low, as in a worn out motor. Maybe it just can't spin that prop any longer. Perhaps robert graham could post his numbers from his nice running 90 to see if that could be part of the puzzle.

 

[ajp1977]

no conclusion?

 

[Geisie]

I have a yellow and a green light on my speedo guage and the yellow light flashes back and forth to the green light when i am operating the boat. Any help would be appreciated. The motor runs fine but i am concerned about the intermittent flashing.Could it have to do with the oil injection?

 

[99yam40]

0ld thread,
please do not post on old threads
Follow the tips at the top and start your own with all your info

 

[jbcurt00]

I have a yellow and a green light on my speedo guage and the yellow light flashes back and forth to the green light when i am operating the boat. Any help would be appreciated. The motor runs fine but i am concerned about the intermittent flashing.Could it have to do with the oil injection?

0ld thread,
please do not post on old threads
Follow the tips at the top and start your own with all your info

Yep ^^^

Closed