Cold start primer solenoid issues-'86 Evinrude 150 hp

3899

Seaman
Joined
Jul 17, 2005
Messages
68
Hello, trying to figure out the fuel primer. It's an '86 Evinrude 150 hp that has had the VRO bypassed, but I think it's still using the VRO fuel pump. Long story kinda short, It has always been cold blooded but has always started. Would bogg once in a while on take off. On a cold Mich morning it wouldn't start. I bypassed the fuel filter and ran the fuel line directly to the pump, and it fired right up with hardly a crank. Ran great...with no bogg. Thought I had it Macgyvered good enough to use the day untill I returned home. But after about an hour or two of drift fishing, it fired right up and was letting it warm a little when it stalled. Then it wouldn't start. It would pop and kick the starter out, but wouldn't run. I had a buddy drag it back to the dock and came home with my depression. After a week, I decided to dig in and diagnose. Good spark, plenty of fuel to pump. I put a vacuum gauge on the pump and it started to pump, but then went to 0 vac. Tested comp and have around 90 lbs even on all cyls, (untested gauge I bougt at an auction). Blew out cylinders and plugs and then after cranking over, heard a click from the fuel pump. Retested the vac and now has good vacuum pull. Pulled primer line to top carb off to see if it had fuel, and still none, but had plenty with valve in bypass and pumping ball. Cranked over and popped right off, barely cranked. Now I'm getting somewhere. Found that barely any fuel is pumping in primer mode...solenoid does click every time. How much fuel should be spitting out of primer hose into carb? Fires up cold every time now in bypass mode, but will not in primer possition (cold after setting all night). Time for a new one? Last night it would push a small stream, but with air bubbles too. Sorry so long of a post. The motor runs like a dream otherwise.
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: Cold start primer solenoid issues-'86 Evinrude 150 hp

The primer is not a pump, it just releases the fuel under pressure from the system into the engine. If no fuel pressure - no primer function.
Normally the primer bulb needs to be pumped hard before priming. Just turning the engine over by the starter might not be enough, unless the fuel pump (VRO type) is at the beginning of its 'stroke'. Engines with the smaller non-VRO pump a different situation as they pulse and pump for every revolution of the engine. The VRO may 'click' once every 20 second or some 30 revs on the starter.
 

3899

Seaman
Joined
Jul 17, 2005
Messages
68
Re: Cold start primer solenoid issues-'86 Evinrude 150 hp

So why does it start so hard cold now? It fires right away in the bypass mode, but seems like it hardly gets fuel in the normal mode. I have plenty of fuel to the solenoid and the "bulb" is hard. With it running, I can feel the vacuum on the port that the primar supply hose connects to. I haven't put the vac gauge on that port yet, but would think it would be enough to pull the fuel into the carb. I'll keep tinkering with it this week.
Thanks for the help!
 
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