1988 OMC V4 Timing

[Solittle]

I want to check and adjust, if necessary, the timing on both of my 1988 OMC V4 Sea Drives.<br /><br />I checked both motors tonight using the method described in a post a couple of months back (plugs out and grounded, throttle wide open - set timing four degrees less than called for in the specs.). The specs for my motors call for 28 degrees before TDC so the value I would be looking for is 24 degrees.<br /><br />One motor checks out at 16 degrees and the other at 14 degrees. First question is what is the affect of the timing as it is now set (16 & 14 instead of 24) and what changes can I expect if I change it to the 24??<br /><br />Now the fun part - These are Sea Drive motors and they do not have the usual timing adjustment screw under the flywheel with the black rubber stopper on the end. There is an assembly on the side of the motor which contains a thing that looks somewhat like an automotive universal joint. This assembly contains the linkage from the throttle cable to the carbs to the rod which changes the timing. There is a linkage rod in this assembly that may be the adjustment but neither of the manuals that I have show it. Anybody run into this?<br /><br />I also wonder if the part of the procedure which calls for the timing to be set at 4 degrees less than the spec (in my case 24 d) would apply to the Sea Drive set-up since the linkage is different??

 

[clanton]

Re: 1988 OMC V4 Timing

Depends on the engine, A V4 crossflow and looper were made that year. Are you getting timing spec from carbuator cover? Got model number?<br /><br />The crossflow may have a plastic clip at the linkage arm with different slots in the clip,if timing off more the 2 degrees try different slot. and the mounting screw for the clip is eccentric and can move the timing 2/3 degrees. Final timing check should be done at 5000 rpms timing full advance. Also final timing specs probley were retarded 4 degrees by SB for reg gas.

 

[Joe Reeves]

Re: 1988 OMC V4 Timing

SoLittle..... That 1988 engine. Is it a crossflow (metal carburetors) or a loop charged engine (plastic carburetors), and what is the horsepower or engine rating (2.6 litre etc)??<br /><br />I cannot visualize the engine not having a spark advance stop, nor the timing readings you're receiving. After you reply to the above, I'll check into it to see if I can be of any help.<br /><br />You are taking a reading from #1 clyinder? Standing in back of the engine, top right cylinder?

 

[Solittle]

Re: 1988 OMC V4 Timing

Joe - If you are perplexed then I'm in big trouble. Let this be a challenge. Some more info from this end:<br /><br />Model Numbers: 16AMPHD - both motors are 1.6L and have two metal carbs.<br /><br />Serial Numbers: R 1512161 and R 15121166<br /><br />Timing taken from numer one cly which is top right looking from the back of the motors.<br /><br />28 degrees is on a sticker on the cover for the carbs.<br /><br />I can confirm that ther is no adjustment screw with a black rubber tip facing the rear of the motor to limit the spark advance. There is a spark advance rod from the timer base assembly which fits into the middle hole of a small nylon piece at the top of an arm which is part of this assembly which I tried to describe above and which I think is unique to the Sea Drive (with this u joint thing in the linkage). I believe that this assembly is OMC original design and not some after market add-on.<br /><br />I have a 1979 OMC Evinrude V4 140 hp manual, an OMC V6 Sea Drive manual and a Clymer (various motors) manual. They do not cover this nor do they indicate the effect on performance if the timing is not set correctly. I am a bit concerned on fiddling with this.<br /><br />Both motors ran fairly well the last time out though they would not idle well. I took it to a "OMC Trained" shop for adjustment and they idled fairly well after that but seemed to lack power. I have had this rig for 6 years and my gut tells me that the timing has never been set correctly.<br /><br />The motors push a 1988 23' Wellcraft CC (heavy boat).<br /><br />Howard Werner<br />Miami Fl

 

[clanton]

Re: 1988 OMC V4 Timing

It is a 1987 engine. To change the timing move the timer linkage to a different slot in nylon piece. Small adjustments are made with the eccentric screw that holds the nylon piece. This adjustment is same as standard outboard that year. The 4 degree retarded full advanced timing is for engines 1985 and below, SB 2159 Rev.1 dated October, 1986.

 

[clanton]

Re: 1988 OMC V4 Timing

If you have Clymer manual ISBN 0-89287-555-0 look on page 244,245 fig 52,and 53. I made a mistake on the eccentric screw, it is the screw that holds the roller in the slot in the linkage that moves the timer linkage arm.

 

[Solittle]

Re: 1988 OMC V4 Timing

Clanton - I must be getting senile as it looks like you found what I have been looking for. I found the referenced pages in my Clymer manual (I have the same manual) and it looks like what I have. You can even see the yoke to that U joint I referred to in my original post at the bottom left of figure 52.<br /><br />Will have at it this weekend.<br /><br />And thanks for taking the time to help. That is what this board seems to be about.<br /><br />Howard