92 PRo V 150 hop up help needed

[Chuck_NJ]

I have a 92 pro v 150 that i recently installed parts from a 225 to increase performance. I replaced the reed blocks carbs devider plate and tuner with a hydrotec. The instalation went well motor started and sounded fine idled fine.

Here is the problem . I wam running it on a 92 basscat pantera 2. Before the hop up the best i ran was 57.8 with a trophy 24 at 5500 rpms and 60 mph with yamaha 25m at 5300 rpms

When i went to the lake with great hopes of increased top end. this is the results. The holeshot seemed much stronger but as we got up to speed and fully trimmed out with the 25m prop all i was able to get was 5100 rpms and 47mph. I raised and lowerend the engine to both extreams a little at a time and no matter where the engine height is all i could get was 5100 rpms and 47 mph.

I talk to the guy that sold me the parts and he has been doing this stuff for years, This gent Ray from TN is a super great guy he feels there is a fuel restriction. I check the filters and pumps for leakage none found. Also the new plugs installed showed one amuch browner then the rest dont know if this plug was fouled . would one dead cylinder limit the engine to 5100 rpms ? what do you people think ?


I ran a compression test yesterday all cylinders 115 psi


What drives me crazy is that i am a automotive mechnaic but have no experance trobleshooting 2 stokes i pulled each wire while idling all seem to have a rpm drop and firing.

What would be the proper stradegy to diagnose?

Modified by Chuck_NJ at 9:07 AM 5/16/2006


Modified by Chuck_NJ at 10:08 AM 5/16/2006

[Hamfisted]

What do the sparkplugs look like? Dark? It might be a question of compression and being able to burn all the fuel flowing into it with the bigger carbs. What year motor did the carbs come off of? Were the carbs torn down and thoroughly cleaned out before the install? If they sat on a shelf for a long time they probably got gummed up inside.
Yes, loss of one cylinder would drop your top rpms down like that.

Mike

[Chuck_NJ]

well had it on the lake again today same results . I took the air housing off and noticed that the bottom carb was puksating i guess there is a problem with the reed blocks i installed. plan on removing manfold agian and see whats up. Should light pass under reeds when shining from ouside looking into block? How do you know if they are sealing corectly?

[Hamfisted]

Off hand I'd say no light should pass through the reed assembly with the motor off, maybe one's just misaligned or something. I guess you just used the stock stainless reeds off the 225? Try a set of Boyessen reeds or some from HydroTec if you can't get those to work right.

Mike


Modified by Hamfisted at 1:15 PM 5/17/2006

[Chuck_NJ]

I want to set the record stright about a fine gentleman that Has helped me without ever asking for any money. This person that i bought my parts from is a absolute genntleman and probably the most knowlegeble person in reguards to these yamaha motors. My problem i am certain has to do with my instalation and not anthing this person sold me. I am only asking in these forums as I am trying to gleen information from everone else if they have ever had this type of problem maybe they could help. I am a automotive mechanic aqnd we have these forums we bounce info off each others. I hope that nobody is taking my posts the wrong way as i have the utmost respect and admiraition for Ray from TN

[Chuck_NJ]

I may have solved my problem , took carbs apart set floats blew out jets an nozzles installed boyesen reeds and man does it sound differnt on the hose sounds like its got a ton more power hope this works on the lake

[Chuck_NJ]

well i had mixed results on lake today. started out boat holeshot was tremendous rpms came up to 5600 turning the 25m and got 55mph its still less then the stock prov150 but better then last week, after several passes i tried adjusting engine height restarted motor and to my disappointment it sounded like crap again and felt like it was missing i was back to the 5100 rpms and the 45mphs. I am starting to thing there is something strage going on with the carbs.

[Chuck_NJ]

disassembled carbs replaced needles and found that the air bleeds for several of the main jets here way to small. Hydrotec was able to give me the right size to drill them out to. Ran boat today with 25m holeshot great turned 5700 rpms and 55mphs almost back to stock speeds may be time to play with engine height. only problem is loading the boat i tore up the 25m. will have to go to my 24 trophy i think now that prop bay be to small. all in all i am making some progress.


i dont understand thiough i can feel a great increase in power on the holeshot i am still losing a little speed over stock config and ideas???