1988 yamaha 225 (how do i start this engine?)

[terrencemclean]

i dont have a control box or cables,... is there any other way i can connect the battery and touch wires to get this started. i just need to see it run. thanks.

 

[Asainz320]

Re: 1988 yamaha 225 (how do i start this engine?)

Just get a battery and some GOOD jumper cables. The cable has to be heavy duty, some cheap jumper cable just wont do it right.

Just give some power to the stater motor and you can accelerate by opening the carbs manually. Before you start it up look for a way to kill the engine. a kill switch cable or something, or just disconnect the gas and let it run out of it. Be really careful if you disconnect the gas line, you can spill some and if you make any spark you will have a fire going.

 

[rodbolt]

Re: 1988 yamaha 225 (how do i start this engine?)

best thing is to simply test spark and compression, if both are good mount it,rebuild the carbs and replace the fuel pumps.
if it hasnt been done now would be a good time to change the water pump t-stats and popit valve grommit.
may as well start off with everything in good shape.
if its a salt water motor first thing I would check is the shift shaft for excessive rust/corrosion.

 

[terrencemclean]

Re: 1988 yamaha 225 (how do i start this engine?)

doesn't the computer have to get power from battery, b4 there can be spark??

 

[rodbolt]

Re: 1988 yamaha 225 (how do i start this engine?)

no, not if you bypass the computer with the A&B connectors.
it may be best if you have a tech look at it.
its a prime start engine as well as a firly advanced micro processor for its time.
to accuratly do any testing with the system,other than a compression test, you really should have 12V to the ECU via the key on yellow wire in the harness.
that setup still ran 6 pulser coils, with the computer in bypass configuration there will be no timing change, idle will be fixed high and top speed cannot be reached.
but with the crank position sensor disconnected its not gonna work right anyway.
can ya give us a port and stbd view as well ?

 

[terrencemclean]

Re: 1988 yamaha 225 (how do i start this engine?)

 

[rodbolt]

Re: 1988 yamaha 225 (how do i start this engine?)

ok
yours is in fact the 88,89 style.
it is NOT prime start and has choke shutters.
it also has a TPS and a fixed timer base(pulser coil) assy.
bic timing is fixed at 7*BTDC and modified by inputs from the TPS and CPS as well as the coolant temp sensor at cold start.
that system used a knock sensor as well.
if the ECU fails the ECU can be bypassed to run in a limited fashion.
idle speed will increase and top speed cannot be reached.
last pulser coil I neded required a flywheel/pulser coil kit. 1200 dollars or so.
but it didnt aply to all models just ones in a specific seriel group.
my suggestion would be to find all the correct parts,oil tank,trim harnes,main hrnes and key switch mount it hook it all up correctly then continue, either that or pas on the project.
that system drove a lot of techs nuts for some reason.
we also had issues with the first few years of that design TPS.
it would develop flat spots.

if it were me in your shoes I would find a knowledgeble tech with experience on the 87-90 V6 excell and 225s to crarefully inspect it.

 

[terrencemclean]

Re: 1988 yamaha 225 (how do i start this engine?)

thanks alot

 

[rodbolt]

Re: 1988 yamaha 225 (how do i start this engine?)

Ray may still see a lot of those engines, they went away with the 90 or so production run. the ECU changed.
I dont see many in my area due to saltwater corrosion.
but they were very solid with few electrical isues other than the early desighn TPS.
however it seems it was way more complex than to many techs could grasp.
for its time it was about the most complex ign system on the market with the suzuki running a close second.
OMC was still playing with quick start which never really did work right and merc was still burning up stators like peanuts.
actually its a very simple system that worked very well, it did require the use and knowledge of a DVM to test plus knowledge of what each sensor did and what happened if it did not.

 

[Ray Neudecker]

Re: 1988 yamaha 225 (how do i start this engine?)

I still deal with a lot of them. They are still surviving well in fresh water country. I have tons of the sensors,TPS's CDI's, ect where we have converted over to race motors a lot of them.
You can do a compression test without the harness and if it is good, then you have the makings of a great motor. The TPS was a soft spot but an ohmeter will be a great help in checking it. Email me at neudecray@hotmail.com if you need any parts or help.

 

[terrencemclean]

Re: 1988 yamaha 225 (how do i start this engine?)

compression is a perfect 110 on all cylinders, its the spark im trying to test without the harness...

 

[rodbolt]

Re: 1988 yamaha 225 (how do i start this engine?)

then run a set of battery cables from the engine to a battery,hook up your spark tester,search this forum for a home made one, jump the A&B CDI/ECU leads, at the stater solinoid unplug the brown wire and take the end coming from the solinoid to the positive lead on the solinoid. if the CDI and pulser coils are good it will spark.
but with the CPS disconnected the ECU wont work correctly anyway.

 

[Ray Neudecker]

Re: 1988 yamaha 225 (how do i start this engine?)

Also note, the 110 compression across the board is not right. That motor should run 130 0n 1 and 2, 120 on 3 and 4, and about 115 0n 5 and 6.
Note this are approximate numbers as all compression numbers tend to vary with different guages. However the port heights and heads vary from one cylinder to the other on these motors and you should not have even compression across the board. A leakdown test should be performed.